xref: /petsc/src/ksp/pc/impls/pbjacobi/pbjacobi.c (revision f3fe499b4cc4d64bf04aa4f5e4963dcc4eb56541)
1 #define PETSCKSP_DLL
2 
3 /*
4    Include files needed for the PBJacobi preconditioner:
5      pcimpl.h - private include file intended for use by all preconditioners
6 */
7 
8 #include "private/pcimpl.h"   /*I "petscpc.h" I*/
9 
10 /*
11    Private context (data structure) for the PBJacobi preconditioner.
12 */
13 typedef struct {
14   MatScalar   *diag;
15   PetscInt    bs,mbs;
16 } PC_PBJacobi;
17 
18 /*
19    Currently only implemented for baij matrices and directly access baij
20   data structures.
21 */
22 #include "../src/mat/impls/baij/mpi/mpibaij.h"
23 #include "../src/mat/blockinvert.h"
24 
25 #undef __FUNCT__
26 #define __FUNCT__ "PCApply_PBJacobi_2"
27 static PetscErrorCode PCApply_PBJacobi_2(PC pc,Vec x,Vec y)
28 {
29   PC_PBJacobi     *jac = (PC_PBJacobi*)pc->data;
30   PetscErrorCode  ierr;
31   PetscInt        i,m = jac->mbs;
32   const MatScalar *diag = jac->diag;
33   PetscScalar     x0,x1,*xx,*yy;
34 
35   PetscFunctionBegin;
36   ierr = VecGetArray(x,&xx);CHKERRQ(ierr);
37   ierr = VecGetArray(y,&yy);CHKERRQ(ierr);
38   for (i=0; i<m; i++) {
39     x0 = xx[2*i]; x1 = xx[2*i+1];
40     yy[2*i]   = diag[0]*x0 + diag[2]*x1;
41     yy[2*i+1] = diag[1]*x0 + diag[3]*x1;
42     diag     += 4;
43   }
44   ierr = VecRestoreArray(x,&xx);CHKERRQ(ierr);
45   ierr = VecRestoreArray(y,&yy);CHKERRQ(ierr);
46   ierr = PetscLogFlops(6.0*m);CHKERRQ(ierr);
47   PetscFunctionReturn(0);
48 }
49 #undef __FUNCT__
50 #define __FUNCT__ "PCApply_PBJacobi_3"
51 static PetscErrorCode PCApply_PBJacobi_3(PC pc,Vec x,Vec y)
52 {
53   PC_PBJacobi     *jac = (PC_PBJacobi*)pc->data;
54   PetscErrorCode  ierr;
55   PetscInt        i,m = jac->mbs;
56   const MatScalar *diag = jac->diag;
57   PetscScalar     x0,x1,x2,*xx,*yy;
58 
59   PetscFunctionBegin;
60   ierr = VecGetArray(x,&xx);CHKERRQ(ierr);
61   ierr = VecGetArray(y,&yy);CHKERRQ(ierr);
62   for (i=0; i<m; i++) {
63     x0 = xx[3*i]; x1 = xx[3*i+1]; x2 = xx[3*i+2];
64     yy[3*i]   = diag[0]*x0 + diag[3]*x1 + diag[6]*x2;
65     yy[3*i+1] = diag[1]*x0 + diag[4]*x1 + diag[7]*x2;
66     yy[3*i+2] = diag[2]*x0 + diag[5]*x1 + diag[8]*x2;
67     diag     += 9;
68   }
69   ierr = VecRestoreArray(x,&xx);CHKERRQ(ierr);
70   ierr = VecRestoreArray(y,&yy);CHKERRQ(ierr);
71   ierr = PetscLogFlops(15.0*m);CHKERRQ(ierr);
72   PetscFunctionReturn(0);
73 }
74 #undef __FUNCT__
75 #define __FUNCT__ "PCApply_PBJacobi_4"
76 static PetscErrorCode PCApply_PBJacobi_4(PC pc,Vec x,Vec y)
77 {
78   PC_PBJacobi      *jac = (PC_PBJacobi*)pc->data;
79   PetscErrorCode   ierr;
80   PetscInt         i,m = jac->mbs;
81   const MatScalar  *diag = jac->diag;
82   PetscScalar      x0,x1,x2,x3,*xx,*yy;
83 
84   PetscFunctionBegin;
85   ierr = VecGetArray(x,&xx);CHKERRQ(ierr);
86   ierr = VecGetArray(y,&yy);CHKERRQ(ierr);
87   for (i=0; i<m; i++) {
88     x0 = xx[4*i]; x1 = xx[4*i+1]; x2 = xx[4*i+2]; x3 = xx[4*i+3];
89     yy[4*i]   = diag[0]*x0 + diag[4]*x1 + diag[8]*x2  + diag[12]*x3;
90     yy[4*i+1] = diag[1]*x0 + diag[5]*x1 + diag[9]*x2  + diag[13]*x3;
91     yy[4*i+2] = diag[2]*x0 + diag[6]*x1 + diag[10]*x2 + diag[14]*x3;
92     yy[4*i+3] = diag[3]*x0 + diag[7]*x1 + diag[11]*x2 + diag[15]*x3;
93     diag     += 16;
94   }
95   ierr = VecRestoreArray(x,&xx);CHKERRQ(ierr);
96   ierr = VecRestoreArray(y,&yy);CHKERRQ(ierr);
97   ierr = PetscLogFlops(28.0*m);CHKERRQ(ierr);
98   PetscFunctionReturn(0);
99 }
100 #undef __FUNCT__
101 #define __FUNCT__ "PCApply_PBJacobi_5"
102 static PetscErrorCode PCApply_PBJacobi_5(PC pc,Vec x,Vec y)
103 {
104   PC_PBJacobi     *jac = (PC_PBJacobi*)pc->data;
105   PetscErrorCode  ierr;
106   PetscInt        i,m = jac->mbs;
107   const MatScalar *diag = jac->diag;
108   PetscScalar     x0,x1,x2,x3,x4,*xx,*yy;
109 
110   PetscFunctionBegin;
111   ierr = VecGetArray(x,&xx);CHKERRQ(ierr);
112   ierr = VecGetArray(y,&yy);CHKERRQ(ierr);
113   for (i=0; i<m; i++) {
114     x0 = xx[5*i]; x1 = xx[5*i+1]; x2 = xx[5*i+2]; x3 = xx[5*i+3]; x4 = xx[5*i+4];
115     yy[5*i]   = diag[0]*x0 + diag[5]*x1 + diag[10]*x2  + diag[15]*x3 + diag[20]*x4;
116     yy[5*i+1] = diag[1]*x0 + diag[6]*x1 + diag[11]*x2  + diag[16]*x3 + diag[21]*x4;
117     yy[5*i+2] = diag[2]*x0 + diag[7]*x1 + diag[12]*x2 + diag[17]*x3 + diag[22]*x4;
118     yy[5*i+3] = diag[3]*x0 + diag[8]*x1 + diag[13]*x2 + diag[18]*x3 + diag[23]*x4;
119     yy[5*i+4] = diag[4]*x0 + diag[9]*x1 + diag[14]*x2 + diag[19]*x3 + diag[24]*x4;
120     diag     += 25;
121   }
122   ierr = VecRestoreArray(x,&xx);CHKERRQ(ierr);
123   ierr = VecRestoreArray(y,&yy);CHKERRQ(ierr);
124   ierr = PetscLogFlops(45.0*m);CHKERRQ(ierr);
125   PetscFunctionReturn(0);
126 }
127 /* -------------------------------------------------------------------------- */
128 #undef __FUNCT__
129 #define __FUNCT__ "PCSetUp_PBJacobi"
130 static PetscErrorCode PCSetUp_PBJacobi(PC pc)
131 {
132   PC_PBJacobi    *jac = (PC_PBJacobi*)pc->data;
133   PetscErrorCode ierr;
134   PetscMPIInt    size;
135   PetscTruth     seqbaij,mpibaij,baij;
136   Mat            A = pc->pmat;
137   Mat_SeqBAIJ    *a;
138 
139   PetscFunctionBegin;
140   ierr = PetscTypeCompare((PetscObject)pc->pmat,MATSEQBAIJ,&seqbaij);CHKERRQ(ierr);
141   ierr = PetscTypeCompare((PetscObject)pc->pmat,MATMPIBAIJ,&mpibaij);CHKERRQ(ierr);
142   ierr = PetscTypeCompare((PetscObject)pc->pmat,MATBAIJ,&baij);CHKERRQ(ierr);
143   if (!seqbaij && !mpibaij && !baij) SETERRQ(((PetscObject)pc)->comm,PETSC_ERR_SUP,"Currently only supports BAIJ matrices");
144   ierr = MPI_Comm_size(((PetscObject)pc)->comm,&size);CHKERRQ(ierr);
145   if (mpibaij || (baij && (size > 1))) A = ((Mat_MPIBAIJ*)A->data)->A;
146   if (A->rmap->n != A->cmap->n) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Supported only for square matrices and square storage");
147 
148   ierr        =  MatSeqBAIJInvertBlockDiagonal(A);CHKERRQ(ierr);
149   a           = (Mat_SeqBAIJ*)A->data;
150   jac->diag   = a->idiag;
151   jac->bs     = A->rmap->bs;
152   jac->mbs    = a->mbs;
153   switch (jac->bs){
154     case 2:
155       pc->ops->apply = PCApply_PBJacobi_2;
156       break;
157     case 3:
158       pc->ops->apply = PCApply_PBJacobi_3;
159       break;
160     case 4:
161       pc->ops->apply = PCApply_PBJacobi_4;
162       break;
163     case 5:
164       pc->ops->apply = PCApply_PBJacobi_5;
165       break;
166     default:
167       SETERRQ1(((PetscObject)pc)->comm,PETSC_ERR_SUP,"not supported for block size %D",jac->bs);
168   }
169 
170   PetscFunctionReturn(0);
171 }
172 /* -------------------------------------------------------------------------- */
173 #undef __FUNCT__
174 #define __FUNCT__ "PCDestroy_PBJacobi"
175 static PetscErrorCode PCDestroy_PBJacobi(PC pc)
176 {
177   PC_PBJacobi    *jac = (PC_PBJacobi*)pc->data;
178   PetscErrorCode ierr;
179 
180   PetscFunctionBegin;
181   /*
182       Free the private data structure that was hanging off the PC
183   */
184   ierr = PetscFree(jac);CHKERRQ(ierr);
185   PetscFunctionReturn(0);
186 }
187 /* -------------------------------------------------------------------------- */
188 /*MC
189      PCPBJACOBI - Point block Jacobi
190 
191    Level: beginner
192 
193   Concepts: point block Jacobi
194 
195    Notes: Only implemented for the BAIJ matrix formats.
196 
197 .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC
198 
199 M*/
200 
201 EXTERN_C_BEGIN
202 #undef __FUNCT__
203 #define __FUNCT__ "PCCreate_PBJacobi"
204 PetscErrorCode PETSCKSP_DLLEXPORT PCCreate_PBJacobi(PC pc)
205 {
206   PC_PBJacobi    *jac;
207   PetscErrorCode ierr;
208 
209   PetscFunctionBegin;
210 
211   /*
212      Creates the private data structure for this preconditioner and
213      attach it to the PC object.
214   */
215   ierr      = PetscNewLog(pc,PC_PBJacobi,&jac);CHKERRQ(ierr);
216   pc->data  = (void*)jac;
217 
218   /*
219      Initialize the pointers to vectors to ZERO; these will be used to store
220      diagonal entries of the matrix for fast preconditioner application.
221   */
222   jac->diag          = 0;
223 
224   /*
225       Set the pointers for the functions that are provided above.
226       Now when the user-level routines (such as PCApply(), PCDestroy(), etc.)
227       are called, they will automatically call these functions.  Note we
228       choose not to provide a couple of these functions since they are
229       not needed.
230   */
231   pc->ops->apply               = 0; /*set depending on the block size */
232   pc->ops->applytranspose      = 0;
233   pc->ops->setup               = PCSetUp_PBJacobi;
234   pc->ops->destroy             = PCDestroy_PBJacobi;
235   pc->ops->setfromoptions      = 0;
236   pc->ops->view                = 0;
237   pc->ops->applyrichardson     = 0;
238   pc->ops->applysymmetricleft  = 0;
239   pc->ops->applysymmetricright = 0;
240   PetscFunctionReturn(0);
241 }
242 EXTERN_C_END
243 
244 
245