xref: /petsc/src/mat/impls/aij/mpi/crl/mcrl.c (revision 1128540423b0e543a2d50f9645353fc1286bdec2)
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   if (crl->icols) {
37     ierr = PetscFree2(crl->acols,crl->icols);CHKERRQ(ierr);
38   }
39   /* Free the Mat_CRL struct itself. */
40   ierr = PetscFree(crl);CHKERRQ(ierr);
41 
42   /* Change the type of A back to MPIAIJ and use MatDestroy_MPIAIJ()
43    * to destroy everything that remains. */
44   ierr = PetscObjectChangeTypeName( (PetscObject)A, MATMPIAIJ);CHKERRQ(ierr);
45   /* Note that I don't call MatSetType().  I believe this is because that
46    * is only to be called when *building* a matrix. */
47   ierr = (*A->ops->destroy)(A);CHKERRQ(ierr);
48   PetscFunctionReturn(0);
49 }
50 
51 #undef __FUNCT__
52 #define __FUNCT__ "MPICRL_create_crl"
53 PetscErrorCode MPICRL_create_crl(Mat A)
54 {
55   Mat_MPIAIJ     *a = (Mat_MPIAIJ *)(A)->data;
56   Mat_SeqAIJ     *Aij = (Mat_SeqAIJ*)(a->A->data), *Bij = (Mat_SeqAIJ*)(a->B->data);
57   Mat_CRL        *crl = (Mat_CRL*) A->spptr;
58   PetscInt       m = A->m;  /* Number of rows in the matrix. */
59   PetscInt       nd = a->A->n; /* number of columns in diagonal portion */
60   PetscInt       *aj = Aij->j,*bj = Bij->j;  /* From the CSR representation; points to the beginning  of each row. */
61   PetscInt       i, j,rmax = 0,*icols, *ailen = Aij->ilen, *bilen = Bij->ilen;
62   PetscScalar    *aa = Aij->a,*ba = Bij->a,*acols,*array;
63   PetscErrorCode ierr;
64 
65   PetscFunctionBegin;
66   /* determine the row with the most columns */
67   for (i=0; i<m; i++) {
68     rmax = PetscMax(rmax,ailen[i]+bilen[i]);
69   }
70   crl->nz   = Aij->nz+Bij->nz;
71   crl->m    = A->m;
72   crl->rmax = rmax;
73   ierr  = PetscMalloc2(rmax*m,PetscScalar,&crl->acols,rmax*m,PetscInt,&crl->icols);CHKERRQ(ierr);
74   acols = crl->acols;
75   icols = crl->icols;
76   for (i=0; i<m; i++) {
77     for (j=0; j<ailen[i]; j++) {
78       acols[j*m+i] = *aa++;
79       icols[j*m+i] = *aj++;
80     }
81     for (;j<ailen[i]+bilen[i]; j++) {
82       acols[j*m+i] = *ba++;
83       icols[j*m+i] = nd + *bj++;
84     }
85     for (;j<rmax; j++) { /* empty column entries */
86       acols[j*m+i] = 0.0;
87       icols[j*m+i] = (j) ? icols[(j-1)*m+i] : 0;  /* handle case where row is EMPTY */
88     }
89   }
90   ierr = PetscLogInfo((A,"MPICRL_create_crl: Percentage of 0's introduced for vectorized multiply %g\n",1.0-((double)(Bij->nz + Bij->nz))/((double)(rmax*m))));
91 
92   ierr = PetscMalloc((a->B->n+nd)*sizeof(PetscScalar),&array);CHKERRQ(ierr);
93   /* xwork array is actually Bij->n+nd long, but we define xwork this length so can copy into it */
94   ierr = VecCreateMPIWithArray(A->comm,nd,PETSC_DECIDE,array,&crl->xwork);CHKERRQ(ierr);
95   ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,a->B->n,array+nd,&crl->fwork);CHKERRQ(ierr);
96   crl->xscat = a->Mvctx;
97   PetscFunctionReturn(0);
98 }
99 
100 #undef __FUNCT__
101 #define __FUNCT__ "MatAssemblyEnd_MPICRL"
102 PetscErrorCode MatAssemblyEnd_MPICRL(Mat A, MatAssemblyType mode)
103 {
104   PetscErrorCode ierr;
105   Mat_CRL        *crl = (Mat_CRL*) A->spptr;
106   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
107   Mat_SeqAIJ     *Aij = (Mat_SeqAIJ*)(a->A->data), *Bij = (Mat_SeqAIJ*)(a->A->data);
108 
109   PetscFunctionBegin;
110   if (mode == MAT_FLUSH_ASSEMBLY) PetscFunctionReturn(0);
111 
112   /* Since a MATMPICRL matrix is really just a MATMPIAIJ with some
113    * extra information, call the AssemblyEnd routine for a MATMPIAIJ.
114    * I'm not sure if this is the best way to do this, but it avoids
115    * a lot of code duplication.
116    * I also note that currently MATMPICRL doesn't know anything about
117    * the Mat_CompressedRow data structure that MPIAIJ now uses when there
118    * are many zero rows.  If the MPIAIJ assembly end routine decides to use
119    * this, this may break things.  (Don't know... haven't looked at it.) */
120   Aij->inode.use = PETSC_FALSE;
121   Bij->inode.use = PETSC_FALSE;
122   (*crl->AssemblyEnd)(A, mode);
123 
124   /* Now calculate the permutation and grouping information. */
125   ierr = MPICRL_create_crl(A);CHKERRQ(ierr);
126   PetscFunctionReturn(0);
127 }
128 
129 extern PetscErrorCode MatMult_CRL(Mat,Vec,Vec);
130 extern PetscErrorCode MatDuplicate_CRL(Mat,MatDuplicateOption,Mat*);
131 
132 /* MatConvert_MPIAIJ_MPICRL converts a MPIAIJ matrix into a
133  * MPICRL matrix.  This routine is called by the MatCreate_MPICRL()
134  * routine, but can also be used to convert an assembled MPIAIJ matrix
135  * into a MPICRL one. */
136 EXTERN_C_BEGIN
137 #undef __FUNCT__
138 #define __FUNCT__ "MatConvert_MPIAIJ_MPICRL"
139 PetscErrorCode PETSCMAT_DLLEXPORT MatConvert_MPIAIJ_MPICRL(Mat A,MatType type,MatReuse reuse,Mat *newmat)
140 {
141   /* This routine is only called to convert to MATMPICRL
142    * from MATMPIAIJ, so we can ignore 'MatType Type'. */
143   PetscErrorCode ierr;
144   Mat            B = *newmat;
145   Mat_CRL        *crl;
146 
147   PetscFunctionBegin;
148   if (reuse == MAT_INITIAL_MATRIX) {
149     ierr = MatDuplicate(A,MAT_COPY_VALUES,&B);CHKERRQ(ierr);
150   }
151 
152   ierr = PetscNew(Mat_CRL,&crl);CHKERRQ(ierr);
153   B->spptr = (void *) crl;
154 
155   /* Save a pointer to the original MPIAIJ assembly end routine, because we
156    * will want to use it later in the CRL assembly end routine.
157    * Also, save a pointer to the original MPIAIJ Destroy routine, because we
158    * will want to use it in the CRL destroy routine. */
159   crl->AssemblyEnd  = A->ops->assemblyend;
160   crl->MatDestroy   = A->ops->destroy;
161   crl->MatDuplicate = A->ops->duplicate;
162 
163   /* Set function pointers for methods that we inherit from AIJ but
164    * override. */
165   B->ops->duplicate   = MatDuplicate_CRL;
166   B->ops->assemblyend = MatAssemblyEnd_MPICRL;
167   B->ops->destroy     = MatDestroy_MPICRL;
168   B->ops->mult        = MatMult_CRL;
169 
170   /* If A has already been assembled, compute the permutation. */
171   if (A->assembled == PETSC_TRUE) {
172     ierr = MPICRL_create_crl(B);CHKERRQ(ierr);
173   }
174   ierr = PetscObjectChangeTypeName((PetscObject)B,MATMPICRL);CHKERRQ(ierr);
175   *newmat = B;
176   PetscFunctionReturn(0);
177 }
178 EXTERN_C_END
179 
180 
181 #undef __FUNCT__
182 #define __FUNCT__ "MatCreateMPICRL"
183 /*@C
184    MatCreateMPICRL - Creates a sparse matrix of type MPICRL.
185    This type inherits from AIJ, but stores some additional
186    information that is used to allow better vectorization of
187    the matrix-vector product. At the cost of increased storage, the AIJ formatted
188    matrix can be copied to a format in which pieces of the matrix are
189    stored in ELLPACK format, allowing the vectorized matrix multiply
190    routine to use stride-1 memory accesses.  As with the AIJ type, it is
191    important to preallocate matrix storage in order to get good assembly
192    performance.
193 
194    Collective on MPI_Comm
195 
196    Input Parameters:
197 +  comm - MPI communicator, set to PETSC_COMM_SELF
198 .  m - number of rows
199 .  n - number of columns
200 .  nz - number of nonzeros per row (same for all rows)
201 -  nnz - array containing the number of nonzeros in the various rows
202          (possibly different for each row) or PETSC_NULL
203 
204    Output Parameter:
205 .  A - the matrix
206 
207    Notes:
208    If nnz is given then nz is ignored
209 
210    Level: intermediate
211 
212 .keywords: matrix, cray, sparse, parallel
213 
214 .seealso: MatCreate(), MatCreateMPICSRPERM(), MatSetValues()
215 @*/
216 PetscErrorCode PETSCMAT_DLLEXPORT MatCreateMPICRL(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt nz,const PetscInt nnz[],PetscInt onz,const PetscInt onnz[],Mat *A)
217 {
218   PetscErrorCode ierr;
219 
220   PetscFunctionBegin;
221   ierr = MatCreate(comm,A);CHKERRQ(ierr);
222   ierr = MatSetSizes(*A,m,n,m,n);CHKERRQ(ierr);
223   ierr = MatSetType(*A,MATMPICRL);CHKERRQ(ierr);
224   ierr = MatMPIAIJSetPreallocation_MPIAIJ(*A,nz,(PetscInt*)nnz,onz,(PetscInt*)onnz);CHKERRQ(ierr);
225   PetscFunctionReturn(0);
226 }
227 
228 
229 EXTERN_C_BEGIN
230 #undef __FUNCT__
231 #define __FUNCT__ "MatCreate_MPICRL"
232 PetscErrorCode PETSCMAT_DLLEXPORT MatCreate_MPICRL(Mat A)
233 {
234   PetscErrorCode ierr;
235 
236   PetscFunctionBegin;
237   /* Change the type name before calling MatSetType() to force proper construction of MPIAIJ
238      and MATMPICRL types. */
239   ierr = PetscObjectChangeTypeName((PetscObject)A,MATMPICRL);CHKERRQ(ierr);
240   ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);
241   ierr = MatConvert_MPIAIJ_MPICRL(A,MATMPICRL,MAT_REUSE_MATRIX,&A);CHKERRQ(ierr);
242   PetscFunctionReturn(0);
243 }
244 EXTERN_C_END
245 
246