xref: /petsc/src/mat/impls/aij/mpi/crl/mcrl.c (revision 69bb7ac94e38f481a514b28cb10ff7ece56113f9)
1 #define PETSCMAT_DLL
2 
3 /*
4   Defines a matrix-vector product for the MATMPIAIJCRL matrix class.
5   This class is derived from the MATMPIAIJ class and retains the
6   compressed row storage (aka Yale sparse matrix format) but augments
7   it with a column oriented storage that is more efficient for
8   matrix vector products on Vector machines.
9 
10   CRL stands for constant row length (that is the same number of columns
11   is kept (padded with zeros) for each row of the sparse matrix.
12 
13    See src/mat/impls/aij/seq/crl/crl.c for the sequential version
14 */
15 
16 #include "src/mat/impls/aij/mpi/mpiaij.h"
17 #include "src/mat/impls/aij/seq/crl/crl.h"
18 
19 #undef __FUNCT__
20 #define __FUNCT__ "MatDestroy_MPICRL"
21 PetscErrorCode MatDestroy_MPICRL(Mat A)
22 {
23   PetscErrorCode ierr;
24   Mat_CRL        *crl = (Mat_CRL *) A->spptr;
25 
26   /* We are going to convert A back into a MPIAIJ matrix, since we are
27    * eventually going to use MatDestroy_MPIAIJ() to destroy everything
28    * that is not specific to CRL.
29    * In preparation for this, reset the operations pointers in A to
30    * their MPIAIJ versions. */
31   A->ops->assemblyend = crl->AssemblyEnd;
32   A->ops->destroy     = crl->MatDestroy;
33   A->ops->duplicate   = crl->MatDuplicate;
34 
35   /* Free everything in the Mat_CRL data structure. */
36   ierr = PetscFree2(crl->acols,crl->icols);CHKERRQ(ierr);
37   if (crl->fwork) {
38     ierr = VecDestroy(crl->fwork);CHKERRQ(ierr);
39   }
40   if (crl->xwork) {
41     ierr = VecDestroy(crl->xwork);CHKERRQ(ierr);
42   }
43   ierr = PetscFree(crl->array);CHKERRQ(ierr);
44   ierr = PetscFree(crl);CHKERRQ(ierr);
45 
46   /* Change the type of A back to MPIAIJ and use MatDestroy_MPIAIJ()
47    * to destroy everything that remains. */
48   ierr = PetscObjectChangeTypeName( (PetscObject)A, MATMPIAIJ);CHKERRQ(ierr);
49   /* Note that I don't call MatSetType().  I believe this is because that
50    * is only to be called when *building* a matrix. */
51   ierr = (*A->ops->destroy)(A);CHKERRQ(ierr);
52   PetscFunctionReturn(0);
53 }
54 
55 #undef __FUNCT__
56 #define __FUNCT__ "MPICRL_create_crl"
57 PetscErrorCode MPICRL_create_crl(Mat A)
58 {
59   Mat_MPIAIJ     *a = (Mat_MPIAIJ *)(A)->data;
60   Mat_SeqAIJ     *Aij = (Mat_SeqAIJ*)(a->A->data), *Bij = (Mat_SeqAIJ*)(a->B->data);
61   Mat_CRL        *crl = (Mat_CRL*) A->spptr;
62   PetscInt       m = A->rmap.n;  /* Number of rows in the matrix. */
63   PetscInt       nd = a->A->cmap.n; /* number of columns in diagonal portion */
64   PetscInt       *aj = Aij->j,*bj = Bij->j;  /* From the CSR representation; points to the beginning  of each row. */
65   PetscInt       i, j,rmax = 0,*icols, *ailen = Aij->ilen, *bilen = Bij->ilen;
66   PetscScalar    *aa = Aij->a,*ba = Bij->a,*acols,*array;
67   PetscErrorCode ierr;
68 
69   PetscFunctionBegin;
70   /* determine the row with the most columns */
71   for (i=0; i<m; i++) {
72     rmax = PetscMax(rmax,ailen[i]+bilen[i]);
73   }
74   crl->nz   = Aij->nz+Bij->nz;
75   crl->m    = A->rmap.n;
76   crl->rmax = rmax;
77   ierr  = PetscMalloc2(rmax*m,PetscScalar,&crl->acols,rmax*m,PetscInt,&crl->icols);CHKERRQ(ierr);
78   acols = crl->acols;
79   icols = crl->icols;
80   for (i=0; i<m; i++) {
81     for (j=0; j<ailen[i]; j++) {
82       acols[j*m+i] = *aa++;
83       icols[j*m+i] = *aj++;
84     }
85     for (;j<ailen[i]+bilen[i]; j++) {
86       acols[j*m+i] = *ba++;
87       icols[j*m+i] = nd + *bj++;
88     }
89     for (;j<rmax; j++) { /* empty column entries */
90       acols[j*m+i] = 0.0;
91       icols[j*m+i] = (j) ? icols[(j-1)*m+i] : 0;  /* handle case where row is EMPTY */
92     }
93   }
94   ierr = PetscInfo1(A,"Percentage of 0's introduced for vectorized multiply %g\n",1.0-((double)(crl->nz))/((double)(rmax*m)));
95 
96   ierr = PetscMalloc((a->B->cmap.n+nd)*sizeof(PetscScalar),&array);CHKERRQ(ierr);
97   /* xwork array is actually B->n+nd long, but we define xwork this length so can copy into it */
98   ierr = VecCreateMPIWithArray(A->comm,nd,PETSC_DECIDE,array,&crl->xwork);CHKERRQ(ierr);
99   ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,a->B->cmap.n,array+nd,&crl->fwork);CHKERRQ(ierr);
100   crl->array = array;
101   crl->xscat = a->Mvctx;
102   PetscFunctionReturn(0);
103 }
104 
105 #undef __FUNCT__
106 #define __FUNCT__ "MatAssemblyEnd_MPICRL"
107 PetscErrorCode MatAssemblyEnd_MPICRL(Mat A, MatAssemblyType mode)
108 {
109   PetscErrorCode ierr;
110   Mat_CRL        *crl = (Mat_CRL*) A->spptr;
111   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
112   Mat_SeqAIJ     *Aij = (Mat_SeqAIJ*)(a->A->data), *Bij = (Mat_SeqAIJ*)(a->A->data);
113 
114   PetscFunctionBegin;
115   if (mode == MAT_FLUSH_ASSEMBLY) PetscFunctionReturn(0);
116 
117   /* Since a MATMPICRL matrix is really just a MATMPIAIJ with some
118    * extra information, call the AssemblyEnd routine for a MATMPIAIJ.
119    * I'm not sure if this is the best way to do this, but it avoids
120    * a lot of code duplication.
121    * I also note that currently MATMPICRL doesn't know anything about
122    * the Mat_CompressedRow data structure that MPIAIJ now uses when there
123    * are many zero rows.  If the MPIAIJ assembly end routine decides to use
124    * this, this may break things.  (Don't know... haven't looked at it.) */
125   Aij->inode.use = PETSC_FALSE;
126   Bij->inode.use = PETSC_FALSE;
127   (*crl->AssemblyEnd)(A, mode);
128 
129   /* Now calculate the permutation and grouping information. */
130   ierr = MPICRL_create_crl(A);CHKERRQ(ierr);
131   PetscFunctionReturn(0);
132 }
133 
134 extern PetscErrorCode MatMult_CRL(Mat,Vec,Vec);
135 extern PetscErrorCode MatDuplicate_CRL(Mat,MatDuplicateOption,Mat*);
136 
137 /* MatConvert_MPIAIJ_MPICRL converts a MPIAIJ matrix into a
138  * MPICRL matrix.  This routine is called by the MatCreate_MPICRL()
139  * routine, but can also be used to convert an assembled MPIAIJ matrix
140  * into a MPICRL one. */
141 EXTERN_C_BEGIN
142 #undef __FUNCT__
143 #define __FUNCT__ "MatConvert_MPIAIJ_MPICRL"
144 PetscErrorCode PETSCMAT_DLLEXPORT MatConvert_MPIAIJ_MPICRL(Mat A,MatType type,MatReuse reuse,Mat *newmat)
145 {
146   /* This routine is only called to convert to MATMPICRL
147    * from MATMPIAIJ, so we can ignore 'MatType Type'. */
148   PetscErrorCode ierr;
149   Mat            B = *newmat;
150   Mat_CRL        *crl;
151 
152   PetscFunctionBegin;
153   if (reuse == MAT_INITIAL_MATRIX) {
154     ierr = MatDuplicate(A,MAT_COPY_VALUES,&B);CHKERRQ(ierr);
155   }
156 
157   ierr = PetscNew(Mat_CRL,&crl);CHKERRQ(ierr);
158   B->spptr = (void *) crl;
159 
160   /* Save a pointer to the original MPIAIJ assembly end routine, because we
161    * will want to use it later in the CRL assembly end routine.
162    * Also, save a pointer to the original MPIAIJ Destroy routine, because we
163    * will want to use it in the CRL destroy routine. */
164   crl->AssemblyEnd  = A->ops->assemblyend;
165   crl->MatDestroy   = A->ops->destroy;
166   crl->MatDuplicate = A->ops->duplicate;
167 
168   /* Set function pointers for methods that we inherit from AIJ but
169    * override. */
170   B->ops->duplicate   = MatDuplicate_CRL;
171   B->ops->assemblyend = MatAssemblyEnd_MPICRL;
172   B->ops->destroy     = MatDestroy_MPICRL;
173   B->ops->mult        = MatMult_CRL;
174 
175   /* If A has already been assembled, compute the permutation. */
176   if (A->assembled == PETSC_TRUE) {
177     ierr = MPICRL_create_crl(B);CHKERRQ(ierr);
178   }
179   ierr = PetscObjectChangeTypeName((PetscObject)B,MATMPICRL);CHKERRQ(ierr);
180   *newmat = B;
181   PetscFunctionReturn(0);
182 }
183 EXTERN_C_END
184 
185 
186 #undef __FUNCT__
187 #define __FUNCT__ "MatCreateMPICRL"
188 /*@C
189    MatCreateMPICRL - Creates a sparse matrix of type MPICRL.
190    This type inherits from AIJ, but stores some additional
191    information that is used to allow better vectorization of
192    the matrix-vector product. At the cost of increased storage, the AIJ formatted
193    matrix can be copied to a format in which pieces of the matrix are
194    stored in ELLPACK format, allowing the vectorized matrix multiply
195    routine to use stride-1 memory accesses.  As with the AIJ type, it is
196    important to preallocate matrix storage in order to get good assembly
197    performance.
198 
199    Collective on MPI_Comm
200 
201    Input Parameters:
202 +  comm - MPI communicator, set to PETSC_COMM_SELF
203 .  m - number of rows
204 .  n - number of columns
205 .  nz - number of nonzeros per row (same for all rows)
206 -  nnz - array containing the number of nonzeros in the various rows
207          (possibly different for each row) or PETSC_NULL
208 
209    Output Parameter:
210 .  A - the matrix
211 
212    Notes:
213    If nnz is given then nz is ignored
214 
215    Level: intermediate
216 
217 .keywords: matrix, cray, sparse, parallel
218 
219 .seealso: MatCreate(), MatCreateMPICSRPERM(), MatSetValues()
220 @*/
221 PetscErrorCode PETSCMAT_DLLEXPORT MatCreateMPICRL(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt nz,const PetscInt nnz[],PetscInt onz,const PetscInt onnz[],Mat *A)
222 {
223   PetscErrorCode ierr;
224 
225   PetscFunctionBegin;
226   ierr = MatCreate(comm,A);CHKERRQ(ierr);
227   ierr = MatSetSizes(*A,m,n,m,n);CHKERRQ(ierr);
228   ierr = MatSetType(*A,MATMPICRL);CHKERRQ(ierr);
229   ierr = MatMPIAIJSetPreallocation_MPIAIJ(*A,nz,(PetscInt*)nnz,onz,(PetscInt*)onnz);CHKERRQ(ierr);
230   PetscFunctionReturn(0);
231 }
232 
233 
234 EXTERN_C_BEGIN
235 #undef __FUNCT__
236 #define __FUNCT__ "MatCreate_MPICRL"
237 PetscErrorCode PETSCMAT_DLLEXPORT MatCreate_MPICRL(Mat A)
238 {
239   PetscErrorCode ierr;
240 
241   PetscFunctionBegin;
242   /* Change the type name before calling MatSetType() to force proper construction of MPIAIJ
243      and MATMPICRL types. */
244   ierr = PetscObjectChangeTypeName((PetscObject)A,MATMPICRL);CHKERRQ(ierr);
245   ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);
246   ierr = MatConvert_MPIAIJ_MPICRL(A,MATMPICRL,MAT_REUSE_MATRIX,&A);CHKERRQ(ierr);
247   PetscFunctionReturn(0);
248 }
249 EXTERN_C_END
250 
251