xref: /libCEED/rust/libceed-sys/c-src/backends/cuda-ref/ceed-cuda-ref-operator.c (revision 034f99fd28bbd688e3b7ed077b6d504c2f765b9c)
1 // Copyright (c) 2017-2024, Lawrence Livermore National Security, LLC and other CEED contributors.
2 // All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
3 //
4 // SPDX-License-Identifier: BSD-2-Clause
5 //
6 // This file is part of CEED:  http://github.com/ceed
7 
8 #include <ceed.h>
9 #include <ceed/backend.h>
10 #include <ceed/jit-tools.h>
11 #include <assert.h>
12 #include <cuda.h>
13 #include <cuda_runtime.h>
14 #include <stdbool.h>
15 #include <string.h>
16 
17 #include "../cuda/ceed-cuda-common.h"
18 #include "../cuda/ceed-cuda-compile.h"
19 #include "ceed-cuda-ref.h"
20 
21 //------------------------------------------------------------------------------
22 // Destroy operator
23 //------------------------------------------------------------------------------
24 static int CeedOperatorDestroy_Cuda(CeedOperator op) {
25   CeedOperator_Cuda *impl;
26 
27   CeedCallBackend(CeedOperatorGetData(op, &impl));
28 
29   // Apply data
30   CeedCallBackend(CeedFree(&impl->num_points));
31   CeedCallBackend(CeedFree(&impl->skip_rstr_in));
32   CeedCallBackend(CeedFree(&impl->skip_rstr_out));
33   CeedCallBackend(CeedFree(&impl->apply_add_basis_out));
34   CeedCallBackend(CeedFree(&impl->input_field_order));
35   CeedCallBackend(CeedFree(&impl->output_field_order));
36   CeedCallBackend(CeedFree(&impl->input_states));
37 
38   for (CeedInt i = 0; i < impl->num_inputs; i++) {
39     CeedCallBackend(CeedVectorDestroy(&impl->e_vecs_in[i]));
40     CeedCallBackend(CeedVectorDestroy(&impl->q_vecs_in[i]));
41   }
42   CeedCallBackend(CeedFree(&impl->e_vecs_in));
43   CeedCallBackend(CeedFree(&impl->q_vecs_in));
44 
45   for (CeedInt i = 0; i < impl->num_outputs; i++) {
46     CeedCallBackend(CeedVectorDestroy(&impl->e_vecs_out[i]));
47     CeedCallBackend(CeedVectorDestroy(&impl->q_vecs_out[i]));
48   }
49   CeedCallBackend(CeedFree(&impl->e_vecs_out));
50   CeedCallBackend(CeedFree(&impl->q_vecs_out));
51   CeedCallBackend(CeedVectorDestroy(&impl->point_coords_elem));
52 
53   // QFunction assembly data
54   for (CeedInt i = 0; i < impl->num_active_in; i++) {
55     CeedCallBackend(CeedVectorDestroy(&impl->qf_active_in[i]));
56   }
57   CeedCallBackend(CeedFree(&impl->qf_active_in));
58 
59   // Diag data
60   if (impl->diag) {
61     Ceed ceed;
62 
63     CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
64     if (impl->diag->module) {
65       CeedCallCuda(ceed, cuModuleUnload(impl->diag->module));
66     }
67     if (impl->diag->module_point_block) {
68       CeedCallCuda(ceed, cuModuleUnload(impl->diag->module_point_block));
69     }
70     CeedCallCuda(ceed, cudaFree(impl->diag->d_eval_modes_in));
71     CeedCallCuda(ceed, cudaFree(impl->diag->d_eval_modes_out));
72     CeedCallCuda(ceed, cudaFree(impl->diag->d_identity));
73     CeedCallCuda(ceed, cudaFree(impl->diag->d_interp_in));
74     CeedCallCuda(ceed, cudaFree(impl->diag->d_interp_out));
75     CeedCallCuda(ceed, cudaFree(impl->diag->d_grad_in));
76     CeedCallCuda(ceed, cudaFree(impl->diag->d_grad_out));
77     CeedCallCuda(ceed, cudaFree(impl->diag->d_div_in));
78     CeedCallCuda(ceed, cudaFree(impl->diag->d_div_out));
79     CeedCallCuda(ceed, cudaFree(impl->diag->d_curl_in));
80     CeedCallCuda(ceed, cudaFree(impl->diag->d_curl_out));
81     CeedCallBackend(CeedElemRestrictionDestroy(&impl->diag->diag_rstr));
82     CeedCallBackend(CeedElemRestrictionDestroy(&impl->diag->point_block_diag_rstr));
83     CeedCallBackend(CeedVectorDestroy(&impl->diag->elem_diag));
84     CeedCallBackend(CeedVectorDestroy(&impl->diag->point_block_elem_diag));
85   }
86   CeedCallBackend(CeedFree(&impl->diag));
87 
88   if (impl->asmb) {
89     Ceed ceed;
90 
91     CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
92     CeedCallCuda(ceed, cuModuleUnload(impl->asmb->module));
93     CeedCallCuda(ceed, cudaFree(impl->asmb->d_B_in));
94     CeedCallCuda(ceed, cudaFree(impl->asmb->d_B_out));
95   }
96   CeedCallBackend(CeedFree(&impl->asmb));
97 
98   CeedCallBackend(CeedFree(&impl));
99   return CEED_ERROR_SUCCESS;
100 }
101 
102 //------------------------------------------------------------------------------
103 // Setup infields or outfields
104 //------------------------------------------------------------------------------
105 static int CeedOperatorSetupFields_Cuda(CeedQFunction qf, CeedOperator op, bool is_input, bool is_at_points, bool *skip_rstr, bool *apply_add_basis,
106                                         CeedVector *e_vecs, CeedVector *q_vecs, CeedInt num_fields, CeedInt Q, CeedInt num_elem) {
107   Ceed                ceed;
108   CeedQFunctionField *qf_fields;
109   CeedOperatorField  *op_fields;
110 
111   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
112   if (is_input) {
113     CeedCallBackend(CeedOperatorGetFields(op, NULL, &op_fields, NULL, NULL));
114     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
115   } else {
116     CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &op_fields));
117     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
118   }
119 
120   // Loop over fields
121   for (CeedInt i = 0; i < num_fields; i++) {
122     bool         is_strided = false, skip_e_vec = false;
123     CeedSize     q_size;
124     CeedInt      size;
125     CeedEvalMode eval_mode;
126     CeedBasis    basis;
127 
128     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
129     if (eval_mode != CEED_EVAL_WEIGHT) {
130       CeedElemRestriction elem_rstr;
131 
132       // Check whether this field can skip the element restriction:
133       // Must be passive input, with eval_mode NONE, and have a strided restriction with CEED_STRIDES_BACKEND.
134       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[i], &elem_rstr));
135 
136       // First, check whether the field is input or output:
137       if (is_input) {
138         CeedVector l_vec;
139 
140         // Check for passive input
141         CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &l_vec));
142         if (l_vec != CEED_VECTOR_ACTIVE && eval_mode == CEED_EVAL_NONE) {
143           // Check for strided restriction
144           CeedCallBackend(CeedElemRestrictionIsStrided(elem_rstr, &is_strided));
145           if (is_strided) {
146             // Check if vector is already in preferred backend ordering
147             CeedCallBackend(CeedElemRestrictionHasBackendStrides(elem_rstr, &skip_e_vec));
148           }
149         }
150       }
151       if (skip_e_vec) {
152         // Either an active field or strided local vec in backend ordering
153         e_vecs[i] = NULL;
154       } else {
155         CeedCallBackend(CeedElemRestrictionCreateVector(elem_rstr, NULL, &e_vecs[i]));
156       }
157     }
158 
159     switch (eval_mode) {
160       case CEED_EVAL_NONE:
161         CeedCallBackend(CeedQFunctionFieldGetSize(qf_fields[i], &size));
162         q_size = (CeedSize)num_elem * Q * size;
163         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
164         break;
165       case CEED_EVAL_INTERP:
166       case CEED_EVAL_GRAD:
167       case CEED_EVAL_DIV:
168       case CEED_EVAL_CURL:
169         CeedCallBackend(CeedQFunctionFieldGetSize(qf_fields[i], &size));
170         q_size = (CeedSize)num_elem * Q * size;
171         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
172         break;
173       case CEED_EVAL_WEIGHT:  // Only on input fields
174         CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis));
175         q_size = (CeedSize)num_elem * Q;
176         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
177         if (is_at_points) {
178           CeedInt num_points[num_elem];
179 
180           for (CeedInt i = 0; i < num_elem; i++) num_points[i] = Q;
181           CeedCallBackend(
182               CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_NOTRANSPOSE, CEED_EVAL_WEIGHT, CEED_VECTOR_NONE, CEED_VECTOR_NONE, q_vecs[i]));
183         } else {
184           CeedCallBackend(CeedBasisApply(basis, num_elem, CEED_NOTRANSPOSE, CEED_EVAL_WEIGHT, CEED_VECTOR_NONE, q_vecs[i]));
185         }
186         break;
187     }
188   }
189   // Drop duplicate restrictions
190   if (is_input) {
191     for (CeedInt i = 0; i < num_fields; i++) {
192       CeedVector          vec_i;
193       CeedElemRestriction rstr_i;
194 
195       CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec_i));
196       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[i], &rstr_i));
197       for (CeedInt j = i + 1; j < num_fields; j++) {
198         CeedVector          vec_j;
199         CeedElemRestriction rstr_j;
200 
201         CeedCallBackend(CeedOperatorFieldGetVector(op_fields[j], &vec_j));
202         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[j], &rstr_j));
203         if (vec_i == vec_j && rstr_i == rstr_j) {
204           CeedCallBackend(CeedVectorReferenceCopy(e_vecs[i], &e_vecs[j]));
205           skip_rstr[j] = true;
206         }
207       }
208     }
209   } else {
210     for (CeedInt i = num_fields - 1; i >= 0; i--) {
211       CeedVector          vec_i;
212       CeedElemRestriction rstr_i;
213 
214       CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec_i));
215       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[i], &rstr_i));
216       for (CeedInt j = i - 1; j >= 0; j--) {
217         CeedVector          vec_j;
218         CeedElemRestriction rstr_j;
219 
220         CeedCallBackend(CeedOperatorFieldGetVector(op_fields[j], &vec_j));
221         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[j], &rstr_j));
222         if (vec_i == vec_j && rstr_i == rstr_j) {
223           CeedCallBackend(CeedVectorReferenceCopy(e_vecs[i], &e_vecs[j]));
224           skip_rstr[j]       = true;
225           apply_add_basis[i] = true;
226         }
227       }
228     }
229   }
230   return CEED_ERROR_SUCCESS;
231 }
232 
233 //------------------------------------------------------------------------------
234 // CeedOperator needs to connect all the named fields (be they active or passive) to the named inputs and outputs of its CeedQFunction.
235 //------------------------------------------------------------------------------
236 static int CeedOperatorSetup_Cuda(CeedOperator op) {
237   Ceed                ceed;
238   bool                is_setup_done;
239   CeedInt             Q, num_elem, num_input_fields, num_output_fields;
240   CeedQFunctionField *qf_input_fields, *qf_output_fields;
241   CeedQFunction       qf;
242   CeedOperatorField  *op_input_fields, *op_output_fields;
243   CeedOperator_Cuda  *impl;
244 
245   CeedCallBackend(CeedOperatorIsSetupDone(op, &is_setup_done));
246   if (is_setup_done) return CEED_ERROR_SUCCESS;
247 
248   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
249   CeedCallBackend(CeedOperatorGetData(op, &impl));
250   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
251   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
252   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
253   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
254   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
255 
256   // Allocate
257   CeedCallBackend(CeedCalloc(num_input_fields, &impl->e_vecs_in));
258   CeedCallBackend(CeedCalloc(num_output_fields, &impl->e_vecs_out));
259   CeedCallBackend(CeedCalloc(num_input_fields, &impl->skip_rstr_in));
260   CeedCallBackend(CeedCalloc(num_output_fields, &impl->skip_rstr_out));
261   CeedCallBackend(CeedCalloc(num_output_fields, &impl->apply_add_basis_out));
262   CeedCallBackend(CeedCalloc(num_input_fields, &impl->input_field_order));
263   CeedCallBackend(CeedCalloc(num_output_fields, &impl->output_field_order));
264   CeedCallBackend(CeedCalloc(num_input_fields, &impl->input_states));
265   CeedCallBackend(CeedCalloc(num_input_fields, &impl->q_vecs_in));
266   CeedCallBackend(CeedCalloc(num_output_fields, &impl->q_vecs_out));
267   impl->num_inputs  = num_input_fields;
268   impl->num_outputs = num_output_fields;
269 
270   // Set up infield and outfield e-vecs and q-vecs
271   CeedCallBackend(
272       CeedOperatorSetupFields_Cuda(qf, op, true, false, impl->skip_rstr_in, NULL, impl->e_vecs_in, impl->q_vecs_in, num_input_fields, Q, num_elem));
273   CeedCallBackend(CeedOperatorSetupFields_Cuda(qf, op, false, false, impl->skip_rstr_out, impl->apply_add_basis_out, impl->e_vecs_out,
274                                                impl->q_vecs_out, num_output_fields, Q, num_elem));
275 
276   // Reorder fields to allow reuse of buffers
277   impl->max_active_e_vec_len = 0;
278   {
279     bool    is_ordered[CEED_FIELD_MAX];
280     CeedInt curr_index = 0;
281 
282     for (CeedInt i = 0; i < num_input_fields; i++) is_ordered[i] = false;
283     for (CeedInt i = 0; i < num_input_fields; i++) {
284       CeedSize            e_vec_len_i;
285       CeedVector          vec_i;
286       CeedElemRestriction rstr_i;
287 
288       if (is_ordered[i]) continue;
289       is_ordered[i]                       = true;
290       impl->input_field_order[curr_index] = i;
291       curr_index++;
292       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec_i));
293       if (vec_i == CEED_VECTOR_NONE) continue;  // CEED_EVAL_WEIGHT
294       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &rstr_i));
295       CeedCallBackend(CeedElemRestrictionGetEVectorSize(rstr_i, &e_vec_len_i));
296       impl->max_active_e_vec_len = e_vec_len_i > impl->max_active_e_vec_len ? e_vec_len_i : impl->max_active_e_vec_len;
297       for (CeedInt j = i + 1; j < num_input_fields; j++) {
298         CeedVector          vec_j;
299         CeedElemRestriction rstr_j;
300 
301         CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[j], &vec_j));
302         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[j], &rstr_j));
303         if (rstr_i == rstr_j && vec_i == vec_j) {
304           is_ordered[j]                       = true;
305           impl->input_field_order[curr_index] = j;
306           curr_index++;
307         }
308       }
309     }
310   }
311   {
312     bool    is_ordered[CEED_FIELD_MAX];
313     CeedInt curr_index = 0;
314 
315     for (CeedInt i = 0; i < num_output_fields; i++) is_ordered[i] = false;
316     for (CeedInt i = 0; i < num_output_fields; i++) {
317       CeedSize            e_vec_len_i;
318       CeedVector          vec_i;
319       CeedElemRestriction rstr_i;
320 
321       if (is_ordered[i]) continue;
322       is_ordered[i]                        = true;
323       impl->output_field_order[curr_index] = i;
324       curr_index++;
325       CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[i], &vec_i));
326       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[i], &rstr_i));
327       CeedCallBackend(CeedElemRestrictionGetEVectorSize(rstr_i, &e_vec_len_i));
328       impl->max_active_e_vec_len = e_vec_len_i > impl->max_active_e_vec_len ? e_vec_len_i : impl->max_active_e_vec_len;
329       for (CeedInt j = i + 1; j < num_output_fields; j++) {
330         CeedVector          vec_j;
331         CeedElemRestriction rstr_j;
332 
333         CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[j], &vec_j));
334         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[j], &rstr_j));
335         if (rstr_i == rstr_j && vec_i == vec_j) {
336           is_ordered[j]                        = true;
337           impl->output_field_order[curr_index] = j;
338           curr_index++;
339         }
340       }
341     }
342   }
343   CeedCallBackend(CeedOperatorSetSetupDone(op));
344   return CEED_ERROR_SUCCESS;
345 }
346 
347 //------------------------------------------------------------------------------
348 // Restrict Operator Inputs
349 //------------------------------------------------------------------------------
350 static inline int CeedOperatorInputRestrict_Cuda(CeedOperatorField op_input_field, CeedQFunctionField qf_input_field, CeedInt input_field,
351                                                  CeedVector in_vec, const bool skip_active, CeedScalar **e_data, CeedOperator_Cuda *impl,
352                                                  CeedRequest *request) {
353   CeedEvalMode eval_mode;
354   CeedVector   l_vec, e_vec = impl->e_vecs_in[input_field];
355 
356   // Get input vector
357   CeedCallBackend(CeedOperatorFieldGetVector(op_input_field, &l_vec));
358   if (l_vec == CEED_VECTOR_ACTIVE) {
359     if (skip_active) return CEED_ERROR_SUCCESS;
360     else l_vec = in_vec;
361   }
362 
363   // Restriction action
364   CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_field, &eval_mode));
365   if (eval_mode == CEED_EVAL_WEIGHT) {  // Skip
366   } else {
367     if (!e_vec) {
368       // No restriction for this field; read data directly from vec.
369       CeedCallBackend(CeedVectorGetArrayRead(l_vec, CEED_MEM_DEVICE, (const CeedScalar **)e_data));
370     } else {
371       // Restrict, if necessary
372       if (!impl->skip_rstr_in[input_field]) {
373         uint64_t state;
374 
375         CeedCallBackend(CeedVectorGetState(l_vec, &state));
376         if (state != impl->input_states[input_field] || l_vec == in_vec) {
377           CeedElemRestriction elem_rstr;
378 
379           CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_field, &elem_rstr));
380           CeedCallBackend(CeedElemRestrictionApply(elem_rstr, CEED_NOTRANSPOSE, l_vec, e_vec, request));
381         }
382         impl->input_states[input_field] = state;
383       }
384       // Get e-vec
385       CeedCallBackend(CeedVectorGetArrayRead(e_vec, CEED_MEM_DEVICE, (const CeedScalar **)e_data));
386     }
387   }
388   return CEED_ERROR_SUCCESS;
389 }
390 
391 //------------------------------------------------------------------------------
392 // Input Basis Action
393 //------------------------------------------------------------------------------
394 static inline int CeedOperatorInputBasis_Cuda(CeedOperatorField op_input_field, CeedQFunctionField qf_input_field, CeedInt input_field,
395                                               CeedInt num_elem, const bool skip_active, CeedScalar *e_data, CeedOperator_Cuda *impl) {
396   CeedEvalMode eval_mode;
397   CeedVector   e_vec = impl->e_vecs_in[input_field], q_vec = impl->q_vecs_in[input_field];
398 
399   // Skip active input
400   if (skip_active) {
401     CeedVector l_vec;
402 
403     CeedCallBackend(CeedOperatorFieldGetVector(op_input_field, &l_vec));
404     if (l_vec == CEED_VECTOR_ACTIVE) return CEED_ERROR_SUCCESS;
405   }
406 
407   // Basis action
408   CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_field, &eval_mode));
409   switch (eval_mode) {
410     case CEED_EVAL_NONE:
411       CeedCallBackend(CeedVectorSetArray(q_vec, CEED_MEM_DEVICE, CEED_USE_POINTER, e_data));
412       break;
413     case CEED_EVAL_INTERP:
414     case CEED_EVAL_GRAD:
415     case CEED_EVAL_DIV:
416     case CEED_EVAL_CURL: {
417       CeedBasis basis;
418 
419       CeedCallBackend(CeedOperatorFieldGetBasis(op_input_field, &basis));
420       CeedCallBackend(CeedBasisApply(basis, num_elem, CEED_NOTRANSPOSE, eval_mode, e_vec, q_vec));
421       break;
422     }
423     case CEED_EVAL_WEIGHT:
424       break;  // No action
425   }
426   return CEED_ERROR_SUCCESS;
427 }
428 
429 //------------------------------------------------------------------------------
430 // Restore Input Vectors
431 //------------------------------------------------------------------------------
432 static inline int CeedOperatorInputRestore_Cuda(CeedOperatorField op_input_field, CeedQFunctionField qf_input_field, CeedInt input_field,
433                                                 const bool skip_active, CeedScalar **e_data, CeedOperator_Cuda *impl) {
434   CeedEvalMode eval_mode;
435   CeedVector   l_vec, e_vec = impl->e_vecs_in[input_field];
436 
437   // Skip active input
438   CeedCallBackend(CeedOperatorFieldGetVector(op_input_field, &l_vec));
439   if (skip_active && l_vec == CEED_VECTOR_ACTIVE) return CEED_ERROR_SUCCESS;
440 
441   // Restore e-vec
442   CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_field, &eval_mode));
443   if (eval_mode == CEED_EVAL_WEIGHT) {  // Skip
444   } else {
445     if (!e_vec) {  // This was a skip_restriction case
446       CeedCallBackend(CeedVectorRestoreArrayRead(l_vec, (const CeedScalar **)e_data));
447     } else {
448       CeedCallBackend(CeedVectorRestoreArrayRead(e_vec, (const CeedScalar **)e_data));
449     }
450   }
451   return CEED_ERROR_SUCCESS;
452 }
453 
454 //------------------------------------------------------------------------------
455 // Apply and add to output
456 //------------------------------------------------------------------------------
457 static int CeedOperatorApplyAdd_Cuda(CeedOperator op, CeedVector in_vec, CeedVector out_vec, CeedRequest *request) {
458   CeedInt             Q, num_elem, num_input_fields, num_output_fields;
459   CeedScalar         *e_data_in[CEED_FIELD_MAX] = {NULL}, *e_data_out[CEED_FIELD_MAX] = {NULL};
460   CeedQFunctionField *qf_input_fields, *qf_output_fields;
461   CeedQFunction       qf;
462   CeedOperatorField  *op_input_fields, *op_output_fields;
463   CeedOperator_Cuda  *impl;
464 
465   CeedCallBackend(CeedOperatorGetData(op, &impl));
466   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
467   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
468   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
469   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
470   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
471 
472   // Setup
473   CeedCallBackend(CeedOperatorSetup_Cuda(op));
474 
475   // Process inputs
476   for (CeedInt i = 0; i < num_input_fields; i++) {
477     CeedInt field = impl->input_field_order[i];
478 
479     CeedCallBackend(
480         CeedOperatorInputRestrict_Cuda(op_input_fields[field], qf_input_fields[field], field, in_vec, false, &e_data_in[field], impl, request));
481     CeedCallBackend(CeedOperatorInputBasis_Cuda(op_input_fields[field], qf_input_fields[field], field, num_elem, false, e_data_in[field], impl));
482   }
483 
484   // Output pointers, as necessary
485   for (CeedInt i = 0; i < num_output_fields; i++) {
486     CeedEvalMode eval_mode;
487 
488     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
489     if (eval_mode == CEED_EVAL_NONE) {
490       // Set the output Q-Vector to use the E-Vector data directly.
491       CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs_out[i], CEED_MEM_DEVICE, &e_data_out[i]));
492       CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data_out[i]));
493     }
494   }
495 
496   // Q function
497   CeedCallBackend(CeedQFunctionApply(qf, num_elem * Q, impl->q_vecs_in, impl->q_vecs_out));
498 
499   // Restore input arrays
500   for (CeedInt i = 0; i < num_input_fields; i++) {
501     CeedCallBackend(CeedOperatorInputRestore_Cuda(op_input_fields[i], qf_input_fields[i], i, false, &e_data_in[i], impl));
502   }
503 
504   // Output basis apply if needed
505   for (CeedInt i = 0; i < num_output_fields; i++) {
506     CeedInt             field = impl->output_field_order[i];
507     CeedEvalMode        eval_mode;
508     CeedVector          l_vec, e_vec = impl->e_vecs_out[field], q_vec = impl->q_vecs_out[field];
509     CeedElemRestriction elem_rstr;
510     CeedBasis           basis;
511 
512     // Output vector
513     CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[field], &l_vec));
514     if (l_vec == CEED_VECTOR_ACTIVE) l_vec = out_vec;
515 
516     // Basis action
517     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[field], &eval_mode));
518     switch (eval_mode) {
519       case CEED_EVAL_NONE:
520         break;  // No action
521       case CEED_EVAL_INTERP:
522       case CEED_EVAL_GRAD:
523       case CEED_EVAL_DIV:
524       case CEED_EVAL_CURL:
525         CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[field], &basis));
526         if (impl->apply_add_basis_out[field]) {
527           CeedCallBackend(CeedBasisApplyAdd(basis, num_elem, CEED_TRANSPOSE, eval_mode, q_vec, e_vec));
528         } else {
529           CeedCallBackend(CeedBasisApply(basis, num_elem, CEED_TRANSPOSE, eval_mode, q_vec, e_vec));
530         }
531         break;
532       // LCOV_EXCL_START
533       case CEED_EVAL_WEIGHT: {
534         return CeedError(CeedOperatorReturnCeed(op), CEED_ERROR_BACKEND, "CEED_EVAL_WEIGHT cannot be an output evaluation mode");
535         // LCOV_EXCL_STOP
536       }
537     }
538 
539     // Restore evec
540     if (eval_mode == CEED_EVAL_NONE) {
541       CeedCallBackend(CeedVectorRestoreArray(e_vec, &e_data_out[field]));
542     }
543 
544     // Restrict
545     if (impl->skip_rstr_out[field]) continue;
546     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[field], &elem_rstr));
547     CeedCallBackend(CeedElemRestrictionApply(elem_rstr, CEED_TRANSPOSE, e_vec, l_vec, request));
548   }
549   return CEED_ERROR_SUCCESS;
550 }
551 
552 //------------------------------------------------------------------------------
553 // CeedOperator needs to connect all the named fields (be they active or passive) to the named inputs and outputs of its CeedQFunction.
554 //------------------------------------------------------------------------------
555 static int CeedOperatorSetupAtPoints_Cuda(CeedOperator op) {
556   Ceed                ceed;
557   bool                is_setup_done;
558   CeedInt             max_num_points = -1, num_elem, num_input_fields, num_output_fields;
559   CeedQFunctionField *qf_input_fields, *qf_output_fields;
560   CeedQFunction       qf;
561   CeedOperatorField  *op_input_fields, *op_output_fields;
562   CeedOperator_Cuda  *impl;
563 
564   CeedCallBackend(CeedOperatorIsSetupDone(op, &is_setup_done));
565   if (is_setup_done) return CEED_ERROR_SUCCESS;
566 
567   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
568   CeedCallBackend(CeedOperatorGetData(op, &impl));
569   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
570   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
571   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
572   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
573   {
574     CeedElemRestriction rstr_points = NULL;
575 
576     CeedCallBackend(CeedOperatorAtPointsGetPoints(op, &rstr_points, NULL));
577     CeedCallBackend(CeedElemRestrictionGetMaxPointsInElement(rstr_points, &max_num_points));
578     CeedCallBackend(CeedCalloc(num_elem, &impl->num_points));
579     for (CeedInt e = 0; e < num_elem; e++) {
580       CeedInt num_points_elem;
581 
582       CeedCallBackend(CeedElemRestrictionGetNumPointsInElement(rstr_points, e, &num_points_elem));
583       impl->num_points[e] = num_points_elem;
584     }
585   }
586   impl->max_num_points = max_num_points;
587 
588   // Allocate
589   CeedCallBackend(CeedCalloc(num_input_fields, &impl->e_vecs_in));
590   CeedCallBackend(CeedCalloc(num_output_fields, &impl->e_vecs_out));
591   CeedCallBackend(CeedCalloc(num_input_fields, &impl->skip_rstr_in));
592   CeedCallBackend(CeedCalloc(num_output_fields, &impl->skip_rstr_out));
593   CeedCallBackend(CeedCalloc(num_output_fields, &impl->apply_add_basis_out));
594   CeedCallBackend(CeedCalloc(num_input_fields, &impl->input_field_order));
595   CeedCallBackend(CeedCalloc(num_output_fields, &impl->output_field_order));
596   CeedCallBackend(CeedCalloc(num_input_fields, &impl->input_states));
597   CeedCallBackend(CeedCalloc(num_input_fields, &impl->q_vecs_in));
598   CeedCallBackend(CeedCalloc(num_output_fields, &impl->q_vecs_out));
599   impl->num_inputs  = num_input_fields;
600   impl->num_outputs = num_output_fields;
601 
602   // Set up infield and outfield e-vecs and q-vecs
603   CeedCallBackend(CeedOperatorSetupFields_Cuda(qf, op, true, true, impl->skip_rstr_in, NULL, impl->e_vecs_in, impl->q_vecs_in, num_input_fields,
604                                                max_num_points, num_elem));
605   CeedCallBackend(CeedOperatorSetupFields_Cuda(qf, op, false, true, impl->skip_rstr_out, impl->apply_add_basis_out, impl->e_vecs_out,
606                                                impl->q_vecs_out, num_output_fields, max_num_points, num_elem));
607 
608   // Reorder fields to allow reuse of buffers
609   {
610     bool    is_ordered[CEED_FIELD_MAX];
611     CeedInt curr_index = 0;
612 
613     for (CeedInt i = 0; i < num_input_fields; i++) is_ordered[i] = false;
614     for (CeedInt i = 0; i < num_input_fields; i++) {
615       CeedVector          vec_i;
616       CeedElemRestriction rstr_i;
617 
618       if (is_ordered[i]) continue;
619       is_ordered[i]                       = true;
620       impl->input_field_order[curr_index] = i;
621       curr_index++;
622       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec_i));
623       if (vec_i == CEED_VECTOR_NONE) continue;  // CEED_EVAL_WEIGHT
624       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &rstr_i));
625       for (CeedInt j = i + 1; j < num_input_fields; j++) {
626         CeedVector          vec_j;
627         CeedElemRestriction rstr_j;
628 
629         CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[j], &vec_j));
630         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[j], &rstr_j));
631         if (rstr_i == rstr_j && vec_i == vec_j) {
632           is_ordered[j]                       = true;
633           impl->input_field_order[curr_index] = j;
634           curr_index++;
635         }
636       }
637     }
638   }
639   {
640     bool    is_ordered[CEED_FIELD_MAX];
641     CeedInt curr_index = 0;
642 
643     for (CeedInt i = 0; i < num_output_fields; i++) is_ordered[i] = false;
644     for (CeedInt i = 0; i < num_output_fields; i++) {
645       CeedVector          vec_i;
646       CeedElemRestriction rstr_i;
647 
648       if (is_ordered[i]) continue;
649       is_ordered[i]                        = true;
650       impl->output_field_order[curr_index] = i;
651       curr_index++;
652       CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[i], &vec_i));
653       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[i], &rstr_i));
654       for (CeedInt j = i + 1; j < num_output_fields; j++) {
655         CeedVector          vec_j;
656         CeedElemRestriction rstr_j;
657 
658         CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[j], &vec_j));
659         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[j], &rstr_j));
660         if (rstr_i == rstr_j && vec_i == vec_j) {
661           is_ordered[j]                        = true;
662           impl->output_field_order[curr_index] = j;
663           curr_index++;
664         }
665       }
666     }
667   }
668   CeedCallBackend(CeedOperatorSetSetupDone(op));
669   return CEED_ERROR_SUCCESS;
670 }
671 
672 //------------------------------------------------------------------------------
673 // Input Basis Action AtPoints
674 //------------------------------------------------------------------------------
675 static inline int CeedOperatorInputBasisAtPoints_Cuda(CeedOperatorField op_input_field, CeedQFunctionField qf_input_field, CeedInt input_field,
676                                                       CeedInt num_elem, const CeedInt *num_points, const bool skip_active, CeedScalar *e_data,
677                                                       CeedOperator_Cuda *impl) {
678   CeedEvalMode eval_mode;
679   CeedVector   e_vec = impl->e_vecs_in[input_field], q_vec = impl->q_vecs_in[input_field];
680 
681   // Skip active input
682   if (skip_active) {
683     CeedVector l_vec;
684 
685     CeedCallBackend(CeedOperatorFieldGetVector(op_input_field, &l_vec));
686     if (l_vec == CEED_VECTOR_ACTIVE) return CEED_ERROR_SUCCESS;
687   }
688 
689   // Basis action
690   CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_field, &eval_mode));
691   switch (eval_mode) {
692     case CEED_EVAL_NONE:
693       CeedCallBackend(CeedVectorSetArray(q_vec, CEED_MEM_DEVICE, CEED_USE_POINTER, e_data));
694       break;
695     case CEED_EVAL_INTERP:
696     case CEED_EVAL_GRAD:
697     case CEED_EVAL_DIV:
698     case CEED_EVAL_CURL: {
699       CeedBasis basis;
700 
701       CeedCallBackend(CeedOperatorFieldGetBasis(op_input_field, &basis));
702       CeedCallBackend(CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_NOTRANSPOSE, eval_mode, impl->point_coords_elem, e_vec, q_vec));
703       break;
704     }
705     case CEED_EVAL_WEIGHT:
706       break;  // No action
707   }
708   return CEED_ERROR_SUCCESS;
709 }
710 
711 //------------------------------------------------------------------------------
712 // Apply and add to output AtPoints
713 //------------------------------------------------------------------------------
714 static int CeedOperatorApplyAddAtPoints_Cuda(CeedOperator op, CeedVector in_vec, CeedVector out_vec, CeedRequest *request) {
715   CeedInt             max_num_points, *num_points, num_elem, num_input_fields, num_output_fields;
716   CeedScalar         *e_data_in[CEED_FIELD_MAX] = {NULL}, *e_data_out[CEED_FIELD_MAX] = {NULL};
717   CeedQFunctionField *qf_input_fields, *qf_output_fields;
718   CeedQFunction       qf;
719   CeedOperatorField  *op_input_fields, *op_output_fields;
720   CeedOperator_Cuda  *impl;
721 
722   CeedCallBackend(CeedOperatorGetData(op, &impl));
723   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
724   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
725   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
726   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
727 
728   // Setup
729   CeedCallBackend(CeedOperatorSetupAtPoints_Cuda(op));
730   num_points     = impl->num_points;
731   max_num_points = impl->max_num_points;
732 
733   // Get point coordinates
734   if (!impl->point_coords_elem) {
735     CeedVector          point_coords = NULL;
736     CeedElemRestriction rstr_points  = NULL;
737 
738     CeedCallBackend(CeedOperatorAtPointsGetPoints(op, &rstr_points, &point_coords));
739     CeedCallBackend(CeedElemRestrictionCreateVector(rstr_points, NULL, &impl->point_coords_elem));
740     CeedCallBackend(CeedElemRestrictionApply(rstr_points, CEED_NOTRANSPOSE, point_coords, impl->point_coords_elem, request));
741   }
742 
743   // Process inputs
744   for (CeedInt i = 0; i < num_input_fields; i++) {
745     CeedInt field = impl->input_field_order[i];
746 
747     CeedCallBackend(
748         CeedOperatorInputRestrict_Cuda(op_input_fields[field], qf_input_fields[field], field, in_vec, false, &e_data_in[field], impl, request));
749     CeedCallBackend(CeedOperatorInputBasisAtPoints_Cuda(op_input_fields[field], qf_input_fields[field], field, num_elem, num_points, false,
750                                                         e_data_in[field], impl));
751   }
752 
753   // Output pointers, as necessary
754   for (CeedInt i = 0; i < num_output_fields; i++) {
755     CeedEvalMode eval_mode;
756 
757     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
758     if (eval_mode == CEED_EVAL_NONE) {
759       // Set the output Q-Vector to use the E-Vector data directly.
760       CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs_out[i], CEED_MEM_DEVICE, &e_data_out[i]));
761       CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data_out[i]));
762     }
763   }
764 
765   // Q function
766   CeedCallBackend(CeedQFunctionApply(qf, num_elem * max_num_points, impl->q_vecs_in, impl->q_vecs_out));
767 
768   // Restore input arrays
769   for (CeedInt i = 0; i < num_input_fields; i++) {
770     CeedCallBackend(CeedOperatorInputRestore_Cuda(op_input_fields[i], qf_input_fields[i], i, false, &e_data_in[i], impl));
771   }
772 
773   // Output basis apply if needed
774   for (CeedInt i = 0; i < num_output_fields; i++) {
775     CeedInt             field = impl->output_field_order[i];
776     CeedEvalMode        eval_mode;
777     CeedVector          l_vec, e_vec = impl->e_vecs_out[field], q_vec = impl->q_vecs_out[field];
778     CeedElemRestriction elem_rstr;
779     CeedBasis           basis;
780 
781     // Output vector
782     CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[field], &l_vec));
783     if (l_vec == CEED_VECTOR_ACTIVE) l_vec = out_vec;
784 
785     // Basis action
786     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[field], &eval_mode));
787     switch (eval_mode) {
788       case CEED_EVAL_NONE:
789         break;  // No action
790       case CEED_EVAL_INTERP:
791       case CEED_EVAL_GRAD:
792       case CEED_EVAL_DIV:
793       case CEED_EVAL_CURL:
794         CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[field], &basis));
795         if (impl->apply_add_basis_out[field]) {
796           CeedCallBackend(CeedBasisApplyAddAtPoints(basis, num_elem, num_points, CEED_TRANSPOSE, eval_mode, impl->point_coords_elem, q_vec, e_vec));
797         } else {
798           CeedCallBackend(CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_TRANSPOSE, eval_mode, impl->point_coords_elem, q_vec, e_vec));
799         }
800         break;
801       // LCOV_EXCL_START
802       case CEED_EVAL_WEIGHT: {
803         return CeedError(CeedOperatorReturnCeed(op), CEED_ERROR_BACKEND, "CEED_EVAL_WEIGHT cannot be an output evaluation mode");
804         // LCOV_EXCL_STOP
805       }
806     }
807 
808     // Restore evec
809     if (eval_mode == CEED_EVAL_NONE) {
810       CeedCallBackend(CeedVectorRestoreArray(e_vec, &e_data_out[field]));
811     }
812 
813     // Restrict
814     if (impl->skip_rstr_out[field]) continue;
815     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[field], &elem_rstr));
816     CeedCallBackend(CeedElemRestrictionApply(elem_rstr, CEED_TRANSPOSE, e_vec, l_vec, request));
817   }
818   return CEED_ERROR_SUCCESS;
819 }
820 
821 //------------------------------------------------------------------------------
822 // Linear QFunction Assembly Core
823 //------------------------------------------------------------------------------
824 static inline int CeedOperatorLinearAssembleQFunctionCore_Cuda(CeedOperator op, bool build_objects, CeedVector *assembled, CeedElemRestriction *rstr,
825                                                                CeedRequest *request) {
826   Ceed                ceed, ceed_parent;
827   CeedInt             num_active_in, num_active_out, Q, num_elem, num_input_fields, num_output_fields, size;
828   CeedScalar         *assembled_array, *e_data[2 * CEED_FIELD_MAX] = {NULL};
829   CeedVector         *active_inputs;
830   CeedQFunctionField *qf_input_fields, *qf_output_fields;
831   CeedQFunction       qf;
832   CeedOperatorField  *op_input_fields, *op_output_fields;
833   CeedOperator_Cuda  *impl;
834 
835   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
836   CeedCallBackend(CeedOperatorGetFallbackParentCeed(op, &ceed_parent));
837   CeedCallBackend(CeedOperatorGetData(op, &impl));
838   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
839   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
840   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
841   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
842   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
843   active_inputs = impl->qf_active_in;
844   num_active_in = impl->num_active_in, num_active_out = impl->num_active_out;
845 
846   // Setup
847   CeedCallBackend(CeedOperatorSetup_Cuda(op));
848 
849   // Process inputs
850   for (CeedInt i = 0; i < num_input_fields; i++) {
851     CeedCallBackend(CeedOperatorInputRestrict_Cuda(op_input_fields[i], qf_input_fields[i], i, NULL, true, &e_data[i], impl, request));
852     CeedCallBackend(CeedOperatorInputBasis_Cuda(op_input_fields[i], qf_input_fields[i], i, num_elem, true, e_data[i], impl));
853   }
854 
855   // Count number of active input fields
856   if (!num_active_in) {
857     for (CeedInt i = 0; i < num_input_fields; i++) {
858       CeedScalar *q_vec_array;
859       CeedVector  l_vec;
860 
861       // Check if active input
862       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &l_vec));
863       if (l_vec == CEED_VECTOR_ACTIVE) {
864         CeedCallBackend(CeedQFunctionFieldGetSize(qf_input_fields[i], &size));
865         CeedCallBackend(CeedVectorSetValue(impl->q_vecs_in[i], 0.0));
866         CeedCallBackend(CeedVectorGetArray(impl->q_vecs_in[i], CEED_MEM_DEVICE, &q_vec_array));
867         CeedCallBackend(CeedRealloc(num_active_in + size, &active_inputs));
868         for (CeedInt field = 0; field < size; field++) {
869           CeedSize q_size = (CeedSize)Q * num_elem;
870 
871           CeedCallBackend(CeedVectorCreate(ceed, q_size, &active_inputs[num_active_in + field]));
872           CeedCallBackend(
873               CeedVectorSetArray(active_inputs[num_active_in + field], CEED_MEM_DEVICE, CEED_USE_POINTER, &q_vec_array[field * Q * num_elem]));
874         }
875         num_active_in += size;
876         CeedCallBackend(CeedVectorRestoreArray(impl->q_vecs_in[i], &q_vec_array));
877       }
878     }
879     impl->num_active_in = num_active_in;
880     impl->qf_active_in  = active_inputs;
881   }
882 
883   // Count number of active output fields
884   if (!num_active_out) {
885     for (CeedInt i = 0; i < num_output_fields; i++) {
886       CeedVector l_vec;
887 
888       // Check if active output
889       CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[i], &l_vec));
890       if (l_vec == CEED_VECTOR_ACTIVE) {
891         CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[i], &size));
892         num_active_out += size;
893       }
894     }
895     impl->num_active_out = num_active_out;
896   }
897 
898   // Check sizes
899   CeedCheck(num_active_in > 0 && num_active_out > 0, ceed, CEED_ERROR_BACKEND, "Cannot assemble QFunction without active inputs and outputs");
900 
901   // Build objects if needed
902   if (build_objects) {
903     CeedSize l_size     = (CeedSize)num_elem * Q * num_active_in * num_active_out;
904     CeedInt  strides[3] = {1, num_elem * Q, Q}; /* *NOPAD* */
905 
906     // Create output restriction
907     CeedCallBackend(CeedElemRestrictionCreateStrided(ceed_parent, num_elem, Q, num_active_in * num_active_out,
908                                                      (CeedSize)num_active_in * (CeedSize)num_active_out * (CeedSize)num_elem * (CeedSize)Q, strides,
909                                                      rstr));
910     // Create assembled vector
911     CeedCallBackend(CeedVectorCreate(ceed_parent, l_size, assembled));
912   }
913   CeedCallBackend(CeedVectorSetValue(*assembled, 0.0));
914   CeedCallBackend(CeedVectorGetArray(*assembled, CEED_MEM_DEVICE, &assembled_array));
915 
916   // Assemble QFunction
917   for (CeedInt in = 0; in < num_active_in; in++) {
918     // Set Inputs
919     CeedCallBackend(CeedVectorSetValue(active_inputs[in], 1.0));
920     if (num_active_in > 1) {
921       CeedCallBackend(CeedVectorSetValue(active_inputs[(in + num_active_in - 1) % num_active_in], 0.0));
922     }
923     // Set Outputs
924     for (CeedInt out = 0; out < num_output_fields; out++) {
925       CeedVector l_vec;
926 
927       // Get output vector
928       CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[out], &l_vec));
929       // Check if active output
930       if (l_vec == CEED_VECTOR_ACTIVE) {
931         CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[out], CEED_MEM_DEVICE, CEED_USE_POINTER, assembled_array));
932         CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[out], &size));
933         assembled_array += size * Q * num_elem;  // Advance the pointer by the size of the output
934       }
935     }
936     // Apply QFunction
937     CeedCallBackend(CeedQFunctionApply(qf, Q * num_elem, impl->q_vecs_in, impl->q_vecs_out));
938   }
939 
940   // Un-set output q-vecs to prevent accidental overwrite of Assembled
941   for (CeedInt out = 0; out < num_output_fields; out++) {
942     CeedVector l_vec;
943 
944     CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[out], &l_vec));
945     if (l_vec == CEED_VECTOR_ACTIVE) {
946       CeedCallBackend(CeedVectorTakeArray(impl->q_vecs_out[out], CEED_MEM_DEVICE, NULL));
947     }
948   }
949 
950   // Restore input arrays
951   for (CeedInt i = 0; i < num_input_fields; i++) {
952     CeedCallBackend(CeedOperatorInputRestore_Cuda(op_input_fields[i], qf_input_fields[i], i, true, &e_data[i], impl));
953   }
954 
955   // Restore output
956   CeedCallBackend(CeedVectorRestoreArray(*assembled, &assembled_array));
957   return CEED_ERROR_SUCCESS;
958 }
959 
960 //------------------------------------------------------------------------------
961 // Assemble Linear QFunction
962 //------------------------------------------------------------------------------
963 static int CeedOperatorLinearAssembleQFunction_Cuda(CeedOperator op, CeedVector *assembled, CeedElemRestriction *rstr, CeedRequest *request) {
964   return CeedOperatorLinearAssembleQFunctionCore_Cuda(op, true, assembled, rstr, request);
965 }
966 
967 //------------------------------------------------------------------------------
968 // Update Assembled Linear QFunction
969 //------------------------------------------------------------------------------
970 static int CeedOperatorLinearAssembleQFunctionUpdate_Cuda(CeedOperator op, CeedVector assembled, CeedElemRestriction rstr, CeedRequest *request) {
971   return CeedOperatorLinearAssembleQFunctionCore_Cuda(op, false, &assembled, &rstr, request);
972 }
973 
974 //------------------------------------------------------------------------------
975 // Assemble Diagonal Setup
976 //------------------------------------------------------------------------------
977 static inline int CeedOperatorAssembleDiagonalSetup_Cuda(CeedOperator op) {
978   Ceed                ceed;
979   CeedInt             num_input_fields, num_output_fields, num_eval_modes_in = 0, num_eval_modes_out = 0;
980   CeedInt             q_comp, num_nodes, num_qpts;
981   CeedEvalMode       *eval_modes_in = NULL, *eval_modes_out = NULL;
982   CeedBasis           basis_in = NULL, basis_out = NULL;
983   CeedQFunctionField *qf_fields;
984   CeedQFunction       qf;
985   CeedOperatorField  *op_fields;
986   CeedOperator_Cuda  *impl;
987 
988   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
989   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
990   CeedCallBackend(CeedQFunctionGetNumArgs(qf, &num_input_fields, &num_output_fields));
991 
992   // Determine active input basis
993   CeedCallBackend(CeedOperatorGetFields(op, NULL, &op_fields, NULL, NULL));
994   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
995   for (CeedInt i = 0; i < num_input_fields; i++) {
996     CeedVector vec;
997 
998     CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
999     if (vec == CEED_VECTOR_ACTIVE) {
1000       CeedBasis    basis;
1001       CeedEvalMode eval_mode;
1002 
1003       CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis));
1004       CeedCheck(!basis_in || basis_in == basis, ceed, CEED_ERROR_BACKEND,
1005                 "Backend does not implement operator diagonal assembly with multiple active bases");
1006       basis_in = basis;
1007       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1008       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_in, eval_mode, &q_comp));
1009       if (eval_mode != CEED_EVAL_WEIGHT) {
1010         // q_comp = 1 if CEED_EVAL_NONE, CEED_EVAL_WEIGHT caught by QF assembly
1011         CeedCallBackend(CeedRealloc(num_eval_modes_in + q_comp, &eval_modes_in));
1012         for (CeedInt d = 0; d < q_comp; d++) eval_modes_in[num_eval_modes_in + d] = eval_mode;
1013         num_eval_modes_in += q_comp;
1014       }
1015     }
1016   }
1017 
1018   // Determine active output basis
1019   CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &op_fields));
1020   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
1021   for (CeedInt i = 0; i < num_output_fields; i++) {
1022     CeedVector vec;
1023 
1024     CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
1025     if (vec == CEED_VECTOR_ACTIVE) {
1026       CeedBasis    basis;
1027       CeedEvalMode eval_mode;
1028 
1029       CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis));
1030       CeedCheck(!basis_out || basis_out == basis, ceed, CEED_ERROR_BACKEND,
1031                 "Backend does not implement operator diagonal assembly with multiple active bases");
1032       basis_out = basis;
1033       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1034       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_out, eval_mode, &q_comp));
1035       if (eval_mode != CEED_EVAL_WEIGHT) {
1036         // q_comp = 1 if CEED_EVAL_NONE, CEED_EVAL_WEIGHT caught by QF assembly
1037         CeedCallBackend(CeedRealloc(num_eval_modes_out + q_comp, &eval_modes_out));
1038         for (CeedInt d = 0; d < q_comp; d++) eval_modes_out[num_eval_modes_out + d] = eval_mode;
1039         num_eval_modes_out += q_comp;
1040       }
1041     }
1042   }
1043 
1044   // Operator data struct
1045   CeedCallBackend(CeedOperatorGetData(op, &impl));
1046   CeedCallBackend(CeedCalloc(1, &impl->diag));
1047   CeedOperatorDiag_Cuda *diag = impl->diag;
1048 
1049   // Basis matrices
1050   CeedCallBackend(CeedBasisGetNumNodes(basis_in, &num_nodes));
1051   if (basis_in == CEED_BASIS_NONE) num_qpts = num_nodes;
1052   else CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_in, &num_qpts));
1053   const CeedInt interp_bytes     = num_nodes * num_qpts * sizeof(CeedScalar);
1054   const CeedInt eval_modes_bytes = sizeof(CeedEvalMode);
1055   bool          has_eval_none    = false;
1056 
1057   // CEED_EVAL_NONE
1058   for (CeedInt i = 0; i < num_eval_modes_in; i++) has_eval_none = has_eval_none || (eval_modes_in[i] == CEED_EVAL_NONE);
1059   for (CeedInt i = 0; i < num_eval_modes_out; i++) has_eval_none = has_eval_none || (eval_modes_out[i] == CEED_EVAL_NONE);
1060   if (has_eval_none) {
1061     CeedScalar *identity = NULL;
1062 
1063     CeedCallBackend(CeedCalloc(num_nodes * num_qpts, &identity));
1064     for (CeedInt i = 0; i < (num_nodes < num_qpts ? num_nodes : num_qpts); i++) identity[i * num_nodes + i] = 1.0;
1065     CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_identity, interp_bytes));
1066     CeedCallCuda(ceed, cudaMemcpy(diag->d_identity, identity, interp_bytes, cudaMemcpyHostToDevice));
1067     CeedCallBackend(CeedFree(&identity));
1068   }
1069 
1070   // CEED_EVAL_INTERP, CEED_EVAL_GRAD, CEED_EVAL_DIV, and CEED_EVAL_CURL
1071   for (CeedInt in = 0; in < 2; in++) {
1072     CeedFESpace fespace;
1073     CeedBasis   basis = in ? basis_in : basis_out;
1074 
1075     CeedCallBackend(CeedBasisGetFESpace(basis, &fespace));
1076     switch (fespace) {
1077       case CEED_FE_SPACE_H1: {
1078         CeedInt           q_comp_interp, q_comp_grad;
1079         const CeedScalar *interp, *grad;
1080         CeedScalar       *d_interp, *d_grad;
1081 
1082         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_INTERP, &q_comp_interp));
1083         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_GRAD, &q_comp_grad));
1084 
1085         CeedCallBackend(CeedBasisGetInterp(basis, &interp));
1086         CeedCallCuda(ceed, cudaMalloc((void **)&d_interp, interp_bytes * q_comp_interp));
1087         CeedCallCuda(ceed, cudaMemcpy(d_interp, interp, interp_bytes * q_comp_interp, cudaMemcpyHostToDevice));
1088         CeedCallBackend(CeedBasisGetGrad(basis, &grad));
1089         CeedCallCuda(ceed, cudaMalloc((void **)&d_grad, interp_bytes * q_comp_grad));
1090         CeedCallCuda(ceed, cudaMemcpy(d_grad, grad, interp_bytes * q_comp_grad, cudaMemcpyHostToDevice));
1091         if (in) {
1092           diag->d_interp_in = d_interp;
1093           diag->d_grad_in   = d_grad;
1094         } else {
1095           diag->d_interp_out = d_interp;
1096           diag->d_grad_out   = d_grad;
1097         }
1098       } break;
1099       case CEED_FE_SPACE_HDIV: {
1100         CeedInt           q_comp_interp, q_comp_div;
1101         const CeedScalar *interp, *div;
1102         CeedScalar       *d_interp, *d_div;
1103 
1104         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_INTERP, &q_comp_interp));
1105         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_DIV, &q_comp_div));
1106 
1107         CeedCallBackend(CeedBasisGetInterp(basis, &interp));
1108         CeedCallCuda(ceed, cudaMalloc((void **)&d_interp, interp_bytes * q_comp_interp));
1109         CeedCallCuda(ceed, cudaMemcpy(d_interp, interp, interp_bytes * q_comp_interp, cudaMemcpyHostToDevice));
1110         CeedCallBackend(CeedBasisGetDiv(basis, &div));
1111         CeedCallCuda(ceed, cudaMalloc((void **)&d_div, interp_bytes * q_comp_div));
1112         CeedCallCuda(ceed, cudaMemcpy(d_div, div, interp_bytes * q_comp_div, cudaMemcpyHostToDevice));
1113         if (in) {
1114           diag->d_interp_in = d_interp;
1115           diag->d_div_in    = d_div;
1116         } else {
1117           diag->d_interp_out = d_interp;
1118           diag->d_div_out    = d_div;
1119         }
1120       } break;
1121       case CEED_FE_SPACE_HCURL: {
1122         CeedInt           q_comp_interp, q_comp_curl;
1123         const CeedScalar *interp, *curl;
1124         CeedScalar       *d_interp, *d_curl;
1125 
1126         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_INTERP, &q_comp_interp));
1127         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_CURL, &q_comp_curl));
1128 
1129         CeedCallBackend(CeedBasisGetInterp(basis, &interp));
1130         CeedCallCuda(ceed, cudaMalloc((void **)&d_interp, interp_bytes * q_comp_interp));
1131         CeedCallCuda(ceed, cudaMemcpy(d_interp, interp, interp_bytes * q_comp_interp, cudaMemcpyHostToDevice));
1132         CeedCallBackend(CeedBasisGetCurl(basis, &curl));
1133         CeedCallCuda(ceed, cudaMalloc((void **)&d_curl, interp_bytes * q_comp_curl));
1134         CeedCallCuda(ceed, cudaMemcpy(d_curl, curl, interp_bytes * q_comp_curl, cudaMemcpyHostToDevice));
1135         if (in) {
1136           diag->d_interp_in = d_interp;
1137           diag->d_curl_in   = d_curl;
1138         } else {
1139           diag->d_interp_out = d_interp;
1140           diag->d_curl_out   = d_curl;
1141         }
1142       } break;
1143     }
1144   }
1145 
1146   // Arrays of eval_modes
1147   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_eval_modes_in, num_eval_modes_in * eval_modes_bytes));
1148   CeedCallCuda(ceed, cudaMemcpy(diag->d_eval_modes_in, eval_modes_in, num_eval_modes_in * eval_modes_bytes, cudaMemcpyHostToDevice));
1149   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_eval_modes_out, num_eval_modes_out * eval_modes_bytes));
1150   CeedCallCuda(ceed, cudaMemcpy(diag->d_eval_modes_out, eval_modes_out, num_eval_modes_out * eval_modes_bytes, cudaMemcpyHostToDevice));
1151   CeedCallBackend(CeedFree(&eval_modes_in));
1152   CeedCallBackend(CeedFree(&eval_modes_out));
1153   return CEED_ERROR_SUCCESS;
1154 }
1155 
1156 //------------------------------------------------------------------------------
1157 // Assemble Diagonal Setup (Compilation)
1158 //------------------------------------------------------------------------------
1159 static inline int CeedOperatorAssembleDiagonalSetupCompile_Cuda(CeedOperator op, CeedInt use_ceedsize_idx, const bool is_point_block) {
1160   Ceed                ceed;
1161   char               *diagonal_kernel_source;
1162   const char         *diagonal_kernel_path;
1163   CeedInt             num_input_fields, num_output_fields, num_eval_modes_in = 0, num_eval_modes_out = 0;
1164   CeedInt             num_comp, q_comp, num_nodes, num_qpts;
1165   CeedBasis           basis_in = NULL, basis_out = NULL;
1166   CeedQFunctionField *qf_fields;
1167   CeedQFunction       qf;
1168   CeedOperatorField  *op_fields;
1169   CeedOperator_Cuda  *impl;
1170 
1171   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1172   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
1173   CeedCallBackend(CeedQFunctionGetNumArgs(qf, &num_input_fields, &num_output_fields));
1174 
1175   // Determine active input basis
1176   CeedCallBackend(CeedOperatorGetFields(op, NULL, &op_fields, NULL, NULL));
1177   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
1178   for (CeedInt i = 0; i < num_input_fields; i++) {
1179     CeedVector vec;
1180 
1181     CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
1182     if (vec == CEED_VECTOR_ACTIVE) {
1183       CeedEvalMode eval_mode;
1184 
1185       CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis_in));
1186       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1187       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_in, eval_mode, &q_comp));
1188       if (eval_mode != CEED_EVAL_WEIGHT) {
1189         num_eval_modes_in += q_comp;
1190       }
1191     }
1192   }
1193 
1194   // Determine active output basis
1195   CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &op_fields));
1196   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
1197   for (CeedInt i = 0; i < num_output_fields; i++) {
1198     CeedVector vec;
1199 
1200     CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
1201     if (vec == CEED_VECTOR_ACTIVE) {
1202       CeedEvalMode eval_mode;
1203 
1204       CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis_out));
1205       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1206       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_out, eval_mode, &q_comp));
1207       if (eval_mode != CEED_EVAL_WEIGHT) {
1208         num_eval_modes_out += q_comp;
1209       }
1210     }
1211   }
1212 
1213   // Operator data struct
1214   CeedCallBackend(CeedOperatorGetData(op, &impl));
1215   CeedOperatorDiag_Cuda *diag = impl->diag;
1216 
1217   // Assemble kernel
1218   CUmodule *module          = is_point_block ? &diag->module_point_block : &diag->module;
1219   CeedInt   elems_per_block = 1;
1220   CeedCallBackend(CeedBasisGetNumNodes(basis_in, &num_nodes));
1221   CeedCallBackend(CeedBasisGetNumComponents(basis_in, &num_comp));
1222   if (basis_in == CEED_BASIS_NONE) num_qpts = num_nodes;
1223   else CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_in, &num_qpts));
1224   CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-ref-operator-assemble-diagonal.h", &diagonal_kernel_path));
1225   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Diagonal Assembly Kernel Source -----\n");
1226   CeedCallBackend(CeedLoadSourceToBuffer(ceed, diagonal_kernel_path, &diagonal_kernel_source));
1227   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Diagonal Assembly Source Complete! -----\n");
1228   CeedCallCuda(ceed, CeedCompile_Cuda(ceed, diagonal_kernel_source, module, 8, "NUM_EVAL_MODES_IN", num_eval_modes_in, "NUM_EVAL_MODES_OUT",
1229                                       num_eval_modes_out, "NUM_COMP", num_comp, "NUM_NODES", num_nodes, "NUM_QPTS", num_qpts, "USE_CEEDSIZE",
1230                                       use_ceedsize_idx, "USE_POINT_BLOCK", is_point_block ? 1 : 0, "BLOCK_SIZE", num_nodes * elems_per_block));
1231   CeedCallCuda(ceed, CeedGetKernel_Cuda(ceed, *module, "LinearDiagonal", is_point_block ? &diag->LinearPointBlock : &diag->LinearDiagonal));
1232   CeedCallBackend(CeedFree(&diagonal_kernel_path));
1233   CeedCallBackend(CeedFree(&diagonal_kernel_source));
1234   return CEED_ERROR_SUCCESS;
1235 }
1236 
1237 //------------------------------------------------------------------------------
1238 // Assemble Diagonal Core
1239 //------------------------------------------------------------------------------
1240 static inline int CeedOperatorAssembleDiagonalCore_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request, const bool is_point_block) {
1241   Ceed                ceed;
1242   CeedInt             num_elem, num_nodes;
1243   CeedScalar         *elem_diag_array;
1244   const CeedScalar   *assembled_qf_array;
1245   CeedVector          assembled_qf   = NULL, elem_diag;
1246   CeedElemRestriction assembled_rstr = NULL, rstr_in, rstr_out, diag_rstr;
1247   CeedOperator_Cuda  *impl;
1248 
1249   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1250   CeedCallBackend(CeedOperatorGetData(op, &impl));
1251 
1252   // Assemble QFunction
1253   CeedCallBackend(CeedOperatorLinearAssembleQFunctionBuildOrUpdate(op, &assembled_qf, &assembled_rstr, request));
1254   CeedCallBackend(CeedElemRestrictionDestroy(&assembled_rstr));
1255   CeedCallBackend(CeedVectorGetArrayRead(assembled_qf, CEED_MEM_DEVICE, &assembled_qf_array));
1256 
1257   // Setup
1258   if (!impl->diag) CeedCallBackend(CeedOperatorAssembleDiagonalSetup_Cuda(op));
1259   CeedOperatorDiag_Cuda *diag = impl->diag;
1260 
1261   assert(diag != NULL);
1262 
1263   // Assemble kernel if needed
1264   if ((!is_point_block && !diag->LinearDiagonal) || (is_point_block && !diag->LinearPointBlock)) {
1265     CeedSize assembled_length, assembled_qf_length;
1266     CeedInt  use_ceedsize_idx = 0;
1267     CeedCallBackend(CeedVectorGetLength(assembled, &assembled_length));
1268     CeedCallBackend(CeedVectorGetLength(assembled_qf, &assembled_qf_length));
1269     if ((assembled_length > INT_MAX) || (assembled_qf_length > INT_MAX)) use_ceedsize_idx = 1;
1270 
1271     CeedCallBackend(CeedOperatorAssembleDiagonalSetupCompile_Cuda(op, use_ceedsize_idx, is_point_block));
1272   }
1273 
1274   // Restriction and diagonal vector
1275   CeedCallBackend(CeedOperatorGetActiveElemRestrictions(op, &rstr_in, &rstr_out));
1276   CeedCheck(rstr_in == rstr_out, ceed, CEED_ERROR_BACKEND,
1277             "Cannot assemble operator diagonal with different input and output active element restrictions");
1278   if (!is_point_block && !diag->diag_rstr) {
1279     CeedCallBackend(CeedElemRestrictionCreateUnsignedCopy(rstr_out, &diag->diag_rstr));
1280     CeedCallBackend(CeedElemRestrictionCreateVector(diag->diag_rstr, NULL, &diag->elem_diag));
1281   } else if (is_point_block && !diag->point_block_diag_rstr) {
1282     CeedCallBackend(CeedOperatorCreateActivePointBlockRestriction(rstr_out, &diag->point_block_diag_rstr));
1283     CeedCallBackend(CeedElemRestrictionCreateVector(diag->point_block_diag_rstr, NULL, &diag->point_block_elem_diag));
1284   }
1285   diag_rstr = is_point_block ? diag->point_block_diag_rstr : diag->diag_rstr;
1286   elem_diag = is_point_block ? diag->point_block_elem_diag : diag->elem_diag;
1287   CeedCallBackend(CeedVectorSetValue(elem_diag, 0.0));
1288 
1289   // Only assemble diagonal if the basis has nodes, otherwise inputs are null pointers
1290   CeedCallBackend(CeedElemRestrictionGetElementSize(diag_rstr, &num_nodes));
1291   if (num_nodes > 0) {
1292     // Assemble element operator diagonals
1293     CeedCallBackend(CeedElemRestrictionGetNumElements(diag_rstr, &num_elem));
1294     CeedCallBackend(CeedVectorGetArray(elem_diag, CEED_MEM_DEVICE, &elem_diag_array));
1295 
1296     // Compute the diagonal of B^T D B
1297     CeedInt elems_per_block = 1;
1298     CeedInt grid            = CeedDivUpInt(num_elem, elems_per_block);
1299     void   *args[]          = {(void *)&num_elem,      &diag->d_identity,       &diag->d_interp_in,  &diag->d_grad_in, &diag->d_div_in,
1300                                &diag->d_curl_in,       &diag->d_interp_out,     &diag->d_grad_out,   &diag->d_div_out, &diag->d_curl_out,
1301                                &diag->d_eval_modes_in, &diag->d_eval_modes_out, &assembled_qf_array, &elem_diag_array};
1302 
1303     if (is_point_block) {
1304       CeedCallBackend(CeedRunKernelDim_Cuda(ceed, diag->LinearPointBlock, grid, num_nodes, 1, elems_per_block, args));
1305     } else {
1306       CeedCallBackend(CeedRunKernelDim_Cuda(ceed, diag->LinearDiagonal, grid, num_nodes, 1, elems_per_block, args));
1307     }
1308 
1309     // Restore arrays
1310     CeedCallBackend(CeedVectorRestoreArray(elem_diag, &elem_diag_array));
1311     CeedCallBackend(CeedVectorRestoreArrayRead(assembled_qf, &assembled_qf_array));
1312   }
1313 
1314   // Assemble local operator diagonal
1315   CeedCallBackend(CeedElemRestrictionApply(diag_rstr, CEED_TRANSPOSE, elem_diag, assembled, request));
1316 
1317   // Cleanup
1318   CeedCallBackend(CeedVectorDestroy(&assembled_qf));
1319   return CEED_ERROR_SUCCESS;
1320 }
1321 
1322 //------------------------------------------------------------------------------
1323 // Assemble Linear Diagonal
1324 //------------------------------------------------------------------------------
1325 static int CeedOperatorLinearAssembleAddDiagonal_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request) {
1326   CeedCallBackend(CeedOperatorAssembleDiagonalCore_Cuda(op, assembled, request, false));
1327   return CEED_ERROR_SUCCESS;
1328 }
1329 
1330 //------------------------------------------------------------------------------
1331 // Assemble Linear Point Block Diagonal
1332 //------------------------------------------------------------------------------
1333 static int CeedOperatorLinearAssembleAddPointBlockDiagonal_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request) {
1334   CeedCallBackend(CeedOperatorAssembleDiagonalCore_Cuda(op, assembled, request, true));
1335   return CEED_ERROR_SUCCESS;
1336 }
1337 
1338 //------------------------------------------------------------------------------
1339 // Single Operator Assembly Setup
1340 //------------------------------------------------------------------------------
1341 static int CeedSingleOperatorAssembleSetup_Cuda(CeedOperator op, CeedInt use_ceedsize_idx) {
1342   Ceed                ceed;
1343   Ceed_Cuda          *cuda_data;
1344   char               *assembly_kernel_source;
1345   const char         *assembly_kernel_path;
1346   CeedInt             num_input_fields, num_output_fields, num_eval_modes_in = 0, num_eval_modes_out = 0;
1347   CeedInt             elem_size_in, num_qpts_in = 0, num_comp_in, elem_size_out, num_qpts_out, num_comp_out, q_comp;
1348   CeedEvalMode       *eval_modes_in = NULL, *eval_modes_out = NULL;
1349   CeedElemRestriction rstr_in = NULL, rstr_out = NULL;
1350   CeedBasis           basis_in = NULL, basis_out = NULL;
1351   CeedQFunctionField *qf_fields;
1352   CeedQFunction       qf;
1353   CeedOperatorField  *input_fields, *output_fields;
1354   CeedOperator_Cuda  *impl;
1355 
1356   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1357   CeedCallBackend(CeedOperatorGetData(op, &impl));
1358 
1359   // Get intput and output fields
1360   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &input_fields, &num_output_fields, &output_fields));
1361 
1362   // Determine active input basis eval mode
1363   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
1364   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
1365   for (CeedInt i = 0; i < num_input_fields; i++) {
1366     CeedVector vec;
1367 
1368     CeedCallBackend(CeedOperatorFieldGetVector(input_fields[i], &vec));
1369     if (vec == CEED_VECTOR_ACTIVE) {
1370       CeedBasis    basis;
1371       CeedEvalMode eval_mode;
1372 
1373       CeedCallBackend(CeedOperatorFieldGetBasis(input_fields[i], &basis));
1374       CeedCheck(!basis_in || basis_in == basis, ceed, CEED_ERROR_BACKEND, "Backend does not implement operator assembly with multiple active bases");
1375       basis_in = basis;
1376       CeedCallBackend(CeedOperatorFieldGetElemRestriction(input_fields[i], &rstr_in));
1377       CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_in, &elem_size_in));
1378       if (basis_in == CEED_BASIS_NONE) num_qpts_in = elem_size_in;
1379       else CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_in, &num_qpts_in));
1380       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1381       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_in, eval_mode, &q_comp));
1382       if (eval_mode != CEED_EVAL_WEIGHT) {
1383         // q_comp = 1 if CEED_EVAL_NONE, CEED_EVAL_WEIGHT caught by QF Assembly
1384         CeedCallBackend(CeedRealloc(num_eval_modes_in + q_comp, &eval_modes_in));
1385         for (CeedInt d = 0; d < q_comp; d++) {
1386           eval_modes_in[num_eval_modes_in + d] = eval_mode;
1387         }
1388         num_eval_modes_in += q_comp;
1389       }
1390     }
1391   }
1392 
1393   // Determine active output basis; basis_out and rstr_out only used if same as input, TODO
1394   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
1395   for (CeedInt i = 0; i < num_output_fields; i++) {
1396     CeedVector vec;
1397 
1398     CeedCallBackend(CeedOperatorFieldGetVector(output_fields[i], &vec));
1399     if (vec == CEED_VECTOR_ACTIVE) {
1400       CeedBasis    basis;
1401       CeedEvalMode eval_mode;
1402 
1403       CeedCallBackend(CeedOperatorFieldGetBasis(output_fields[i], &basis));
1404       CeedCheck(!basis_out || basis_out == basis, ceed, CEED_ERROR_BACKEND,
1405                 "Backend does not implement operator assembly with multiple active bases");
1406       basis_out = basis;
1407       CeedCallBackend(CeedOperatorFieldGetElemRestriction(output_fields[i], &rstr_out));
1408       CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_out, &elem_size_out));
1409       if (basis_out == CEED_BASIS_NONE) num_qpts_out = elem_size_out;
1410       else CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_out, &num_qpts_out));
1411       CeedCheck(num_qpts_in == num_qpts_out, ceed, CEED_ERROR_UNSUPPORTED,
1412                 "Active input and output bases must have the same number of quadrature points");
1413       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1414       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_out, eval_mode, &q_comp));
1415       if (eval_mode != CEED_EVAL_WEIGHT) {
1416         // q_comp = 1 if CEED_EVAL_NONE, CEED_EVAL_WEIGHT caught by QF Assembly
1417         CeedCallBackend(CeedRealloc(num_eval_modes_out + q_comp, &eval_modes_out));
1418         for (CeedInt d = 0; d < q_comp; d++) {
1419           eval_modes_out[num_eval_modes_out + d] = eval_mode;
1420         }
1421         num_eval_modes_out += q_comp;
1422       }
1423     }
1424   }
1425   CeedCheck(num_eval_modes_in > 0 && num_eval_modes_out > 0, ceed, CEED_ERROR_UNSUPPORTED, "Cannot assemble operator without inputs/outputs");
1426 
1427   CeedCallBackend(CeedCalloc(1, &impl->asmb));
1428   CeedOperatorAssemble_Cuda *asmb = impl->asmb;
1429   asmb->elems_per_block           = 1;
1430   asmb->block_size_x              = elem_size_in;
1431   asmb->block_size_y              = elem_size_out;
1432 
1433   CeedCallBackend(CeedGetData(ceed, &cuda_data));
1434   bool fallback = asmb->block_size_x * asmb->block_size_y * asmb->elems_per_block > cuda_data->device_prop.maxThreadsPerBlock;
1435 
1436   if (fallback) {
1437     // Use fallback kernel with 1D threadblock
1438     asmb->block_size_y = 1;
1439   }
1440 
1441   // Compile kernels
1442   CeedCallBackend(CeedElemRestrictionGetNumComponents(rstr_in, &num_comp_in));
1443   CeedCallBackend(CeedElemRestrictionGetNumComponents(rstr_out, &num_comp_out));
1444   CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-ref-operator-assemble.h", &assembly_kernel_path));
1445   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Assembly Kernel Source -----\n");
1446   CeedCallBackend(CeedLoadSourceToBuffer(ceed, assembly_kernel_path, &assembly_kernel_source));
1447   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Assembly Source Complete! -----\n");
1448   CeedCallBackend(CeedCompile_Cuda(ceed, assembly_kernel_source, &asmb->module, 10, "NUM_EVAL_MODES_IN", num_eval_modes_in, "NUM_EVAL_MODES_OUT",
1449                                    num_eval_modes_out, "NUM_COMP_IN", num_comp_in, "NUM_COMP_OUT", num_comp_out, "NUM_NODES_IN", elem_size_in,
1450                                    "NUM_NODES_OUT", elem_size_out, "NUM_QPTS", num_qpts_in, "BLOCK_SIZE",
1451                                    asmb->block_size_x * asmb->block_size_y * asmb->elems_per_block, "BLOCK_SIZE_Y", asmb->block_size_y,
1452                                    "USE_CEEDSIZE", use_ceedsize_idx));
1453   CeedCallBackend(CeedGetKernel_Cuda(ceed, asmb->module, "LinearAssemble", &asmb->LinearAssemble));
1454   CeedCallBackend(CeedFree(&assembly_kernel_path));
1455   CeedCallBackend(CeedFree(&assembly_kernel_source));
1456 
1457   // Load into B_in, in order that they will be used in eval_modes_in
1458   {
1459     const CeedInt in_bytes           = elem_size_in * num_qpts_in * num_eval_modes_in * sizeof(CeedScalar);
1460     CeedInt       d_in               = 0;
1461     CeedEvalMode  eval_modes_in_prev = CEED_EVAL_NONE;
1462     bool          has_eval_none      = false;
1463     CeedScalar   *identity           = NULL;
1464 
1465     for (CeedInt i = 0; i < num_eval_modes_in; i++) {
1466       has_eval_none = has_eval_none || (eval_modes_in[i] == CEED_EVAL_NONE);
1467     }
1468     if (has_eval_none) {
1469       CeedCallBackend(CeedCalloc(elem_size_in * num_qpts_in, &identity));
1470       for (CeedInt i = 0; i < (elem_size_in < num_qpts_in ? elem_size_in : num_qpts_in); i++) identity[i * elem_size_in + i] = 1.0;
1471     }
1472 
1473     CeedCallCuda(ceed, cudaMalloc((void **)&asmb->d_B_in, in_bytes));
1474     for (CeedInt i = 0; i < num_eval_modes_in; i++) {
1475       const CeedScalar *h_B_in;
1476 
1477       CeedCallBackend(CeedOperatorGetBasisPointer(basis_in, eval_modes_in[i], identity, &h_B_in));
1478       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_in, eval_modes_in[i], &q_comp));
1479       if (q_comp > 1) {
1480         if (i == 0 || eval_modes_in[i] != eval_modes_in_prev) d_in = 0;
1481         else h_B_in = &h_B_in[(++d_in) * elem_size_in * num_qpts_in];
1482       }
1483       eval_modes_in_prev = eval_modes_in[i];
1484 
1485       CeedCallCuda(ceed, cudaMemcpy(&asmb->d_B_in[i * elem_size_in * num_qpts_in], h_B_in, elem_size_in * num_qpts_in * sizeof(CeedScalar),
1486                                     cudaMemcpyHostToDevice));
1487     }
1488 
1489     if (identity) {
1490       CeedCallBackend(CeedFree(&identity));
1491     }
1492   }
1493 
1494   // Load into B_out, in order that they will be used in eval_modes_out
1495   {
1496     const CeedInt out_bytes           = elem_size_out * num_qpts_out * num_eval_modes_out * sizeof(CeedScalar);
1497     CeedInt       d_out               = 0;
1498     CeedEvalMode  eval_modes_out_prev = CEED_EVAL_NONE;
1499     bool          has_eval_none       = false;
1500     CeedScalar   *identity            = NULL;
1501 
1502     for (CeedInt i = 0; i < num_eval_modes_out; i++) {
1503       has_eval_none = has_eval_none || (eval_modes_out[i] == CEED_EVAL_NONE);
1504     }
1505     if (has_eval_none) {
1506       CeedCallBackend(CeedCalloc(elem_size_out * num_qpts_out, &identity));
1507       for (CeedInt i = 0; i < (elem_size_out < num_qpts_out ? elem_size_out : num_qpts_out); i++) identity[i * elem_size_out + i] = 1.0;
1508     }
1509 
1510     CeedCallCuda(ceed, cudaMalloc((void **)&asmb->d_B_out, out_bytes));
1511     for (CeedInt i = 0; i < num_eval_modes_out; i++) {
1512       const CeedScalar *h_B_out;
1513 
1514       CeedCallBackend(CeedOperatorGetBasisPointer(basis_out, eval_modes_out[i], identity, &h_B_out));
1515       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_out, eval_modes_out[i], &q_comp));
1516       if (q_comp > 1) {
1517         if (i == 0 || eval_modes_out[i] != eval_modes_out_prev) d_out = 0;
1518         else h_B_out = &h_B_out[(++d_out) * elem_size_out * num_qpts_out];
1519       }
1520       eval_modes_out_prev = eval_modes_out[i];
1521 
1522       CeedCallCuda(ceed, cudaMemcpy(&asmb->d_B_out[i * elem_size_out * num_qpts_out], h_B_out, elem_size_out * num_qpts_out * sizeof(CeedScalar),
1523                                     cudaMemcpyHostToDevice));
1524     }
1525 
1526     if (identity) {
1527       CeedCallBackend(CeedFree(&identity));
1528     }
1529   }
1530   return CEED_ERROR_SUCCESS;
1531 }
1532 
1533 //------------------------------------------------------------------------------
1534 // Assemble matrix data for COO matrix of assembled operator.
1535 // The sparsity pattern is set by CeedOperatorLinearAssembleSymbolic.
1536 //
1537 // Note that this (and other assembly routines) currently assume only one active input restriction/basis per operator
1538 // (could have multiple basis eval modes).
1539 // TODO: allow multiple active input restrictions/basis objects
1540 //------------------------------------------------------------------------------
1541 static int CeedSingleOperatorAssemble_Cuda(CeedOperator op, CeedInt offset, CeedVector values) {
1542   Ceed                ceed;
1543   CeedSize            values_length = 0, assembled_qf_length = 0;
1544   CeedInt             use_ceedsize_idx = 0, num_elem_in, num_elem_out, elem_size_in, elem_size_out;
1545   CeedScalar         *values_array;
1546   const CeedScalar   *assembled_qf_array;
1547   CeedVector          assembled_qf   = NULL;
1548   CeedElemRestriction assembled_rstr = NULL, rstr_in, rstr_out;
1549   CeedRestrictionType rstr_type_in, rstr_type_out;
1550   const bool         *orients_in = NULL, *orients_out = NULL;
1551   const CeedInt8     *curl_orients_in = NULL, *curl_orients_out = NULL;
1552   CeedOperator_Cuda  *impl;
1553 
1554   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1555   CeedCallBackend(CeedOperatorGetData(op, &impl));
1556 
1557   // Assemble QFunction
1558   CeedCallBackend(CeedOperatorLinearAssembleQFunctionBuildOrUpdate(op, &assembled_qf, &assembled_rstr, CEED_REQUEST_IMMEDIATE));
1559   CeedCallBackend(CeedElemRestrictionDestroy(&assembled_rstr));
1560   CeedCallBackend(CeedVectorGetArrayRead(assembled_qf, CEED_MEM_DEVICE, &assembled_qf_array));
1561 
1562   CeedCallBackend(CeedVectorGetLength(values, &values_length));
1563   CeedCallBackend(CeedVectorGetLength(assembled_qf, &assembled_qf_length));
1564   if ((values_length > INT_MAX) || (assembled_qf_length > INT_MAX)) use_ceedsize_idx = 1;
1565 
1566   // Setup
1567   if (!impl->asmb) CeedCallBackend(CeedSingleOperatorAssembleSetup_Cuda(op, use_ceedsize_idx));
1568   CeedOperatorAssemble_Cuda *asmb = impl->asmb;
1569 
1570   assert(asmb != NULL);
1571 
1572   // Assemble element operator
1573   CeedCallBackend(CeedVectorGetArray(values, CEED_MEM_DEVICE, &values_array));
1574   values_array += offset;
1575 
1576   CeedCallBackend(CeedOperatorGetActiveElemRestrictions(op, &rstr_in, &rstr_out));
1577   CeedCallBackend(CeedElemRestrictionGetNumElements(rstr_in, &num_elem_in));
1578   CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_in, &elem_size_in));
1579 
1580   CeedCallBackend(CeedElemRestrictionGetType(rstr_in, &rstr_type_in));
1581   if (rstr_type_in == CEED_RESTRICTION_ORIENTED) {
1582     CeedCallBackend(CeedElemRestrictionGetOrientations(rstr_in, CEED_MEM_DEVICE, &orients_in));
1583   } else if (rstr_type_in == CEED_RESTRICTION_CURL_ORIENTED) {
1584     CeedCallBackend(CeedElemRestrictionGetCurlOrientations(rstr_in, CEED_MEM_DEVICE, &curl_orients_in));
1585   }
1586 
1587   if (rstr_in != rstr_out) {
1588     CeedCallBackend(CeedElemRestrictionGetNumElements(rstr_out, &num_elem_out));
1589     CeedCheck(num_elem_in == num_elem_out, ceed, CEED_ERROR_UNSUPPORTED,
1590               "Active input and output operator restrictions must have the same number of elements");
1591     CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_out, &elem_size_out));
1592 
1593     CeedCallBackend(CeedElemRestrictionGetType(rstr_out, &rstr_type_out));
1594     if (rstr_type_out == CEED_RESTRICTION_ORIENTED) {
1595       CeedCallBackend(CeedElemRestrictionGetOrientations(rstr_out, CEED_MEM_DEVICE, &orients_out));
1596     } else if (rstr_type_out == CEED_RESTRICTION_CURL_ORIENTED) {
1597       CeedCallBackend(CeedElemRestrictionGetCurlOrientations(rstr_out, CEED_MEM_DEVICE, &curl_orients_out));
1598     }
1599   } else {
1600     elem_size_out    = elem_size_in;
1601     orients_out      = orients_in;
1602     curl_orients_out = curl_orients_in;
1603   }
1604 
1605   // Compute B^T D B
1606   CeedInt shared_mem =
1607       ((curl_orients_in || curl_orients_out ? elem_size_in * elem_size_out : 0) + (curl_orients_in ? elem_size_in * asmb->block_size_y : 0)) *
1608       sizeof(CeedScalar);
1609   CeedInt grid   = CeedDivUpInt(num_elem_in, asmb->elems_per_block);
1610   void   *args[] = {(void *)&num_elem_in, &asmb->d_B_in,     &asmb->d_B_out,      &orients_in,  &curl_orients_in,
1611                     &orients_out,         &curl_orients_out, &assembled_qf_array, &values_array};
1612 
1613   CeedCallBackend(
1614       CeedRunKernelDimShared_Cuda(ceed, asmb->LinearAssemble, grid, asmb->block_size_x, asmb->block_size_y, asmb->elems_per_block, shared_mem, args));
1615 
1616   // Restore arrays
1617   CeedCallBackend(CeedVectorRestoreArray(values, &values_array));
1618   CeedCallBackend(CeedVectorRestoreArrayRead(assembled_qf, &assembled_qf_array));
1619 
1620   // Cleanup
1621   CeedCallBackend(CeedVectorDestroy(&assembled_qf));
1622   if (rstr_type_in == CEED_RESTRICTION_ORIENTED) {
1623     CeedCallBackend(CeedElemRestrictionRestoreOrientations(rstr_in, &orients_in));
1624   } else if (rstr_type_in == CEED_RESTRICTION_CURL_ORIENTED) {
1625     CeedCallBackend(CeedElemRestrictionRestoreCurlOrientations(rstr_in, &curl_orients_in));
1626   }
1627   if (rstr_in != rstr_out) {
1628     if (rstr_type_out == CEED_RESTRICTION_ORIENTED) {
1629       CeedCallBackend(CeedElemRestrictionRestoreOrientations(rstr_out, &orients_out));
1630     } else if (rstr_type_out == CEED_RESTRICTION_CURL_ORIENTED) {
1631       CeedCallBackend(CeedElemRestrictionRestoreCurlOrientations(rstr_out, &curl_orients_out));
1632     }
1633   }
1634   return CEED_ERROR_SUCCESS;
1635 }
1636 
1637 //------------------------------------------------------------------------------
1638 // Assemble Linear QFunction AtPoints
1639 //------------------------------------------------------------------------------
1640 static int CeedOperatorLinearAssembleQFunctionAtPoints_Cuda(CeedOperator op, CeedVector *assembled, CeedElemRestriction *rstr, CeedRequest *request) {
1641   return CeedError(CeedOperatorReturnCeed(op), CEED_ERROR_BACKEND, "Backend does not implement CeedOperatorLinearAssembleQFunction");
1642 }
1643 
1644 //------------------------------------------------------------------------------
1645 // Assemble Linear Diagonal AtPoints
1646 //------------------------------------------------------------------------------
1647 static int CeedOperatorLinearAssembleAddDiagonalAtPoints_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request) {
1648   CeedInt             max_num_points, *num_points, num_elem, num_input_fields, num_output_fields;
1649   CeedScalar         *e_data_in[CEED_FIELD_MAX] = {NULL}, *e_data_out[CEED_FIELD_MAX] = {NULL};
1650   CeedQFunctionField *qf_input_fields, *qf_output_fields;
1651   CeedQFunction       qf;
1652   CeedOperatorField  *op_input_fields, *op_output_fields;
1653   CeedOperator_Cuda  *impl;
1654 
1655   CeedCallBackend(CeedOperatorGetData(op, &impl));
1656   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
1657   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
1658   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
1659   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
1660 
1661   // Setup
1662   CeedCallBackend(CeedOperatorSetupAtPoints_Cuda(op));
1663   num_points     = impl->num_points;
1664   max_num_points = impl->max_num_points;
1665 
1666   // Create separate output e-vecs
1667   if (impl->has_shared_e_vecs) {
1668     for (CeedInt i = 0; i < impl->num_outputs; i++) {
1669       CeedCallBackend(CeedVectorDestroy(&impl->q_vecs_out[i]));
1670       CeedCallBackend(CeedVectorDestroy(&impl->e_vecs_out[i]));
1671     }
1672     CeedCallBackend(CeedOperatorSetupFields_Cuda(qf, op, false, true, impl->skip_rstr_out, impl->apply_add_basis_out, impl->e_vecs_out,
1673                                                  impl->q_vecs_out, num_output_fields, max_num_points, num_elem));
1674   }
1675   impl->has_shared_e_vecs = false;
1676 
1677   // Get point coordinates
1678   if (!impl->point_coords_elem) {
1679     CeedVector          point_coords = NULL;
1680     CeedElemRestriction rstr_points  = NULL;
1681 
1682     CeedCallBackend(CeedOperatorAtPointsGetPoints(op, &rstr_points, &point_coords));
1683     CeedCallBackend(CeedElemRestrictionCreateVector(rstr_points, NULL, &impl->point_coords_elem));
1684     CeedCallBackend(CeedElemRestrictionApply(rstr_points, CEED_NOTRANSPOSE, point_coords, impl->point_coords_elem, request));
1685   }
1686 
1687   // Process inputs
1688   for (CeedInt i = 0; i < num_input_fields; i++) {
1689     CeedCallBackend(CeedOperatorInputRestrict_Cuda(op_input_fields[i], qf_input_fields[i], i, NULL, true, &e_data_in[i], impl, request));
1690     CeedCallBackend(CeedOperatorInputBasisAtPoints_Cuda(op_input_fields[i], qf_input_fields[i], i, num_elem, num_points, true, e_data_in[i], impl));
1691   }
1692 
1693   // Clear active input Qvecs
1694   for (CeedInt i = 0; i < num_input_fields; i++) {
1695     CeedVector vec;
1696 
1697     CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
1698     if (vec != CEED_VECTOR_ACTIVE) continue;
1699     CeedCallBackend(CeedVectorSetValue(impl->q_vecs_in[i], 0.0));
1700   }
1701 
1702   // Output pointers, as necessary
1703   for (CeedInt i = 0; i < num_output_fields; i++) {
1704     CeedEvalMode eval_mode;
1705 
1706     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
1707     if (eval_mode == CEED_EVAL_NONE) {
1708       // Set the output Q-Vector to use the E-Vector data directly.
1709       CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs_out[i], CEED_MEM_DEVICE, &e_data_out[i]));
1710       CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data_out[i]));
1711     }
1712   }
1713 
1714   // Loop over active fields
1715   for (CeedInt i = 0; i < num_input_fields; i++) {
1716     bool                is_active_at_points = true;
1717     CeedInt             elem_size = 1, num_comp_active = 1, e_vec_size = 0;
1718     CeedRestrictionType rstr_type;
1719     CeedVector          l_vec;
1720     CeedElemRestriction elem_rstr;
1721 
1722     CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &l_vec));
1723     // -- Skip non-active input
1724     if (l_vec != CEED_VECTOR_ACTIVE) continue;
1725 
1726     // -- Get active restriction type
1727     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &elem_rstr));
1728     CeedCallBackend(CeedElemRestrictionGetType(elem_rstr, &rstr_type));
1729     is_active_at_points = rstr_type == CEED_RESTRICTION_POINTS;
1730     if (!is_active_at_points) CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
1731     else elem_size = max_num_points;
1732     CeedCallBackend(CeedElemRestrictionGetNumComponents(elem_rstr, &num_comp_active));
1733 
1734     e_vec_size = elem_size * num_comp_active;
1735     for (CeedInt s = 0; s < e_vec_size; s++) {
1736       bool         is_active_input = false;
1737       CeedEvalMode eval_mode;
1738       CeedVector   vec;
1739       CeedBasis    basis;
1740 
1741       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
1742       // Skip non-active input
1743       is_active_input = vec == CEED_VECTOR_ACTIVE;
1744       if (!is_active_input) continue;
1745 
1746       // Update unit vector
1747       if (s == 0) CeedCallBackend(CeedVectorSetValue(impl->e_vecs_in[i], 0.0));
1748       else CeedCallBackend(CeedVectorSetValueStrided(impl->e_vecs_in[i], s - 1, e_vec_size, 0.0));
1749       CeedCallBackend(CeedVectorSetValueStrided(impl->e_vecs_in[i], s, e_vec_size, 1.0));
1750 
1751       // Basis action
1752       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
1753       switch (eval_mode) {
1754         case CEED_EVAL_NONE:
1755           CeedCallBackend(CeedVectorSetArray(impl->q_vecs_in[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data_in[i]));
1756           break;
1757         case CEED_EVAL_INTERP:
1758         case CEED_EVAL_GRAD:
1759         case CEED_EVAL_DIV:
1760         case CEED_EVAL_CURL:
1761           CeedCallBackend(CeedOperatorFieldGetBasis(op_input_fields[i], &basis));
1762           CeedCallBackend(CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_NOTRANSPOSE, eval_mode, impl->point_coords_elem,
1763                                                  impl->e_vecs_in[i], impl->q_vecs_in[i]));
1764           break;
1765         case CEED_EVAL_WEIGHT:
1766           break;  // No action
1767       }
1768 
1769       // Q function
1770       CeedCallBackend(CeedQFunctionApply(qf, num_elem * max_num_points, impl->q_vecs_in, impl->q_vecs_out));
1771 
1772       // Output basis apply if needed
1773       for (CeedInt j = 0; j < num_output_fields; j++) {
1774         bool                is_active_output = false;
1775         CeedInt             elem_size        = 0;
1776         CeedRestrictionType rstr_type;
1777         CeedEvalMode        eval_mode;
1778         CeedVector          l_vec;
1779         CeedElemRestriction elem_rstr;
1780         CeedBasis           basis;
1781 
1782         CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[j], &l_vec));
1783         // ---- Skip non-active output
1784         is_active_output = l_vec == CEED_VECTOR_ACTIVE;
1785         if (!is_active_output) continue;
1786 
1787         // ---- Check if elem size matches
1788         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[j], &elem_rstr));
1789         CeedCallBackend(CeedElemRestrictionGetType(elem_rstr, &rstr_type));
1790         if (is_active_at_points && rstr_type != CEED_RESTRICTION_POINTS) continue;
1791         if (rstr_type == CEED_RESTRICTION_POINTS) {
1792           CeedCallBackend(CeedElemRestrictionGetMaxPointsInElement(elem_rstr, &elem_size));
1793         } else {
1794           CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
1795         }
1796         {
1797           CeedInt num_comp = 0;
1798 
1799           CeedCallBackend(CeedElemRestrictionGetNumComponents(elem_rstr, &num_comp));
1800           if (e_vec_size != num_comp * elem_size) continue;
1801         }
1802 
1803         // Basis action
1804         CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[j], &eval_mode));
1805         switch (eval_mode) {
1806           case CEED_EVAL_NONE:
1807             CeedCallBackend(CeedVectorRestoreArray(impl->e_vecs_out[j], &e_data_out[j]));
1808             break;
1809           case CEED_EVAL_INTERP:
1810           case CEED_EVAL_GRAD:
1811           case CEED_EVAL_DIV:
1812           case CEED_EVAL_CURL:
1813             CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[j], &basis));
1814             CeedCallBackend(CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_TRANSPOSE, eval_mode, impl->point_coords_elem,
1815                                                    impl->q_vecs_out[j], impl->e_vecs_out[j]));
1816             break;
1817           // LCOV_EXCL_START
1818           case CEED_EVAL_WEIGHT: {
1819             return CeedError(CeedOperatorReturnCeed(op), CEED_ERROR_BACKEND, "CEED_EVAL_WEIGHT cannot be an output evaluation mode");
1820             // LCOV_EXCL_STOP
1821           }
1822         }
1823 
1824         // Mask output e-vec
1825         CeedCallBackend(CeedVectorPointwiseMult(impl->e_vecs_out[j], impl->e_vecs_in[i], impl->e_vecs_out[j]));
1826 
1827         // Restrict
1828         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[j], &elem_rstr));
1829         CeedCallBackend(CeedElemRestrictionApply(elem_rstr, CEED_TRANSPOSE, impl->e_vecs_out[j], assembled, request));
1830 
1831         // Reset q_vec for
1832         if (eval_mode == CEED_EVAL_NONE) {
1833           CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs_out[j], CEED_MEM_DEVICE, &e_data_out[j]));
1834           CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[j], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data_out[j]));
1835         }
1836       }
1837 
1838       // Reset vec
1839       if (s == e_vec_size - 1 && i != num_input_fields - 1) CeedCallBackend(CeedVectorSetValue(impl->q_vecs_in[i], 0.0));
1840     }
1841   }
1842 
1843   // Restore CEED_EVAL_NONE
1844   for (CeedInt i = 0; i < num_output_fields; i++) {
1845     CeedEvalMode eval_mode;
1846 
1847     // Get eval_mode
1848     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
1849 
1850     // Restore evec
1851     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
1852     if (eval_mode == CEED_EVAL_NONE) {
1853       CeedCallBackend(CeedVectorRestoreArray(impl->e_vecs_in[i], &e_data_in[i]));
1854     }
1855   }
1856 
1857   // Restore input arrays
1858   for (CeedInt i = 0; i < num_input_fields; i++) {
1859     CeedCallBackend(CeedOperatorInputRestore_Cuda(op_input_fields[i], qf_input_fields[i], i, true, &e_data_in[i], impl));
1860   }
1861   return CEED_ERROR_SUCCESS;
1862 }
1863 
1864 //------------------------------------------------------------------------------
1865 // Create operator
1866 //------------------------------------------------------------------------------
1867 int CeedOperatorCreate_Cuda(CeedOperator op) {
1868   Ceed               ceed;
1869   CeedOperator_Cuda *impl;
1870 
1871   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1872   CeedCallBackend(CeedCalloc(1, &impl));
1873   CeedCallBackend(CeedOperatorSetData(op, impl));
1874 
1875   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunction", CeedOperatorLinearAssembleQFunction_Cuda));
1876   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunctionUpdate", CeedOperatorLinearAssembleQFunctionUpdate_Cuda));
1877   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleAddDiagonal", CeedOperatorLinearAssembleAddDiagonal_Cuda));
1878   CeedCallBackend(
1879       CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleAddPointBlockDiagonal", CeedOperatorLinearAssembleAddPointBlockDiagonal_Cuda));
1880   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleSingle", CeedSingleOperatorAssemble_Cuda));
1881   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "ApplyAdd", CeedOperatorApplyAdd_Cuda));
1882   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "Destroy", CeedOperatorDestroy_Cuda));
1883   return CEED_ERROR_SUCCESS;
1884 }
1885 
1886 //------------------------------------------------------------------------------
1887 // Create operator AtPoints
1888 //------------------------------------------------------------------------------
1889 int CeedOperatorCreateAtPoints_Cuda(CeedOperator op) {
1890   Ceed               ceed;
1891   CeedOperator_Cuda *impl;
1892 
1893   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1894   CeedCallBackend(CeedCalloc(1, &impl));
1895   CeedCallBackend(CeedOperatorSetData(op, impl));
1896 
1897   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunction", CeedOperatorLinearAssembleQFunctionAtPoints_Cuda));
1898   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleAddDiagonal", CeedOperatorLinearAssembleAddDiagonalAtPoints_Cuda));
1899   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "ApplyAdd", CeedOperatorApplyAddAtPoints_Cuda));
1900   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "Destroy", CeedOperatorDestroy_Cuda));
1901   return CEED_ERROR_SUCCESS;
1902 }
1903 
1904 //------------------------------------------------------------------------------
1905