xref: /petsc/src/mat/impls/aij/mpi/crl/mcrl.c (revision ebead697dbf761eb322f829370bbe90b3bd93fa3)
1 
2 /*
3   Defines a matrix-vector product for the MATMPIAIJCRL matrix class.
4   This class is derived from the MATMPIAIJ class and retains the
5   compressed row storage (aka Yale sparse matrix format) but augments
6   it with a column oriented storage that is more efficient for
7   matrix vector products on Vector machines.
8 
9   CRL stands for constant row length (that is the same number of columns
10   is kept (padded with zeros) for each row of the sparse matrix.
11 
12    See src/mat/impls/aij/seq/crl/crl.c for the sequential version
13 */
14 
15 #include <../src/mat/impls/aij/mpi/mpiaij.h>
16 #include <../src/mat/impls/aij/seq/crl/crl.h>
17 
18 PetscErrorCode MatDestroy_MPIAIJCRL(Mat A)
19 {
20   Mat_AIJCRL     *aijcrl = (Mat_AIJCRL*) A->spptr;
21 
22   PetscFunctionBegin;
23   if (aijcrl) {
24     PetscCall(PetscFree2(aijcrl->acols,aijcrl->icols));
25     PetscCall(VecDestroy(&aijcrl->fwork));
26     PetscCall(VecDestroy(&aijcrl->xwork));
27     PetscCall(PetscFree(aijcrl->array));
28   }
29   PetscCall(PetscFree(A->spptr));
30 
31   PetscCall(PetscObjectChangeTypeName((PetscObject)A, MATMPIAIJ));
32   PetscCall(MatDestroy_MPIAIJ(A));
33   PetscFunctionReturn(0);
34 }
35 
36 PetscErrorCode MatMPIAIJCRL_create_aijcrl(Mat A)
37 {
38   Mat_MPIAIJ     *a      = (Mat_MPIAIJ*)(A)->data;
39   Mat_SeqAIJ     *Aij    = (Mat_SeqAIJ*)(a->A->data), *Bij = (Mat_SeqAIJ*)(a->B->data);
40   Mat_AIJCRL     *aijcrl = (Mat_AIJCRL*) A->spptr;
41   PetscInt       m       = A->rmap->n; /* Number of rows in the matrix. */
42   PetscInt       nd      = a->A->cmap->n; /* number of columns in diagonal portion */
43   PetscInt       *aj     = Aij->j,*bj = Bij->j; /* From the CSR representation; points to the beginning  of each row. */
44   PetscInt       i, j,rmax = 0,*icols, *ailen = Aij->ilen, *bilen = Bij->ilen;
45   PetscScalar    *aa = Aij->a,*ba = Bij->a,*acols,*array;
46 
47   PetscFunctionBegin;
48   /* determine the row with the most columns */
49   for (i=0; i<m; i++) {
50     rmax = PetscMax(rmax,ailen[i]+bilen[i]);
51   }
52   aijcrl->nz   = Aij->nz+Bij->nz;
53   aijcrl->m    = A->rmap->n;
54   aijcrl->rmax = rmax;
55 
56   PetscCall(PetscFree2(aijcrl->acols,aijcrl->icols));
57   PetscCall(PetscMalloc2(rmax*m,&aijcrl->acols,rmax*m,&aijcrl->icols));
58   acols = aijcrl->acols;
59   icols = aijcrl->icols;
60   for (i=0; i<m; i++) {
61     for (j=0; j<ailen[i]; j++) {
62       acols[j*m+i] = *aa++;
63       icols[j*m+i] = *aj++;
64     }
65     for (; j<ailen[i]+bilen[i]; j++) {
66       acols[j*m+i] = *ba++;
67       icols[j*m+i] = nd + *bj++;
68     }
69     for (; j<rmax; j++) { /* empty column entries */
70       acols[j*m+i] = 0.0;
71       icols[j*m+i] = (j) ? icols[(j-1)*m+i] : 0;  /* handle case where row is EMPTY */
72     }
73   }
74   PetscCall(PetscInfo(A,"Percentage of 0's introduced for vectorized multiply %g\n",1.0-((double)(aijcrl->nz))/((double)(rmax*m))));
75 
76   PetscCall(PetscFree(aijcrl->array));
77   PetscCall(PetscMalloc1(a->B->cmap->n+nd,&array));
78   /* xwork array is actually B->n+nd long, but we define xwork this length so can copy into it */
79   PetscCall(VecDestroy(&aijcrl->xwork));
80   PetscCall(VecCreateMPIWithArray(PetscObjectComm((PetscObject)A),1,nd,PETSC_DECIDE,array,&aijcrl->xwork));
81   PetscCall(VecDestroy(&aijcrl->fwork));
82   PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF,1,a->B->cmap->n,array+nd,&aijcrl->fwork));
83 
84   aijcrl->array = array;
85   aijcrl->xscat = a->Mvctx;
86   PetscFunctionReturn(0);
87 }
88 
89 PetscErrorCode MatAssemblyEnd_MPIAIJCRL(Mat A, MatAssemblyType mode)
90 {
91   Mat_MPIAIJ     *a   = (Mat_MPIAIJ*)A->data;
92   Mat_SeqAIJ     *Aij = (Mat_SeqAIJ*)(a->A->data), *Bij = (Mat_SeqAIJ*)(a->A->data);
93 
94   PetscFunctionBegin;
95   Aij->inode.use = PETSC_FALSE;
96   Bij->inode.use = PETSC_FALSE;
97 
98   PetscCall(MatAssemblyEnd_MPIAIJ(A,mode));
99   if (mode == MAT_FLUSH_ASSEMBLY) PetscFunctionReturn(0);
100 
101   /* Now calculate the permutation and grouping information. */
102   PetscCall(MatMPIAIJCRL_create_aijcrl(A));
103   PetscFunctionReturn(0);
104 }
105 
106 extern PetscErrorCode MatMult_AIJCRL(Mat,Vec,Vec);
107 extern PetscErrorCode MatDuplicate_AIJCRL(Mat,MatDuplicateOption,Mat*);
108 
109 /* MatConvert_MPIAIJ_MPIAIJCRL converts a MPIAIJ matrix into a
110  * MPIAIJCRL matrix.  This routine is called by the MatCreate_MPIAIJCRL()
111  * routine, but can also be used to convert an assembled MPIAIJ matrix
112  * into a MPIAIJCRL one. */
113 
114 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPIAIJCRL(Mat A,MatType type,MatReuse reuse,Mat *newmat)
115 {
116   Mat            B = *newmat;
117   Mat_AIJCRL     *aijcrl;
118 
119   PetscFunctionBegin;
120   if (reuse == MAT_INITIAL_MATRIX) {
121     PetscCall(MatDuplicate(A,MAT_COPY_VALUES,&B));
122   }
123 
124   PetscCall(PetscNewLog(B,&aijcrl));
125   B->spptr = (void*) aijcrl;
126 
127   /* Set function pointers for methods that we inherit from AIJ but override. */
128   B->ops->duplicate   = MatDuplicate_AIJCRL;
129   B->ops->assemblyend = MatAssemblyEnd_MPIAIJCRL;
130   B->ops->destroy     = MatDestroy_MPIAIJCRL;
131   B->ops->mult        = MatMult_AIJCRL;
132 
133   /* If A has already been assembled, compute the permutation. */
134   if (A->assembled) PetscCall(MatMPIAIJCRL_create_aijcrl(B));
135   PetscCall(PetscObjectChangeTypeName((PetscObject)B,MATMPIAIJCRL));
136   *newmat = B;
137   PetscFunctionReturn(0);
138 }
139 
140 /*@C
141    MatCreateMPIAIJCRL - Creates a sparse matrix of type MPIAIJCRL.
142    This type inherits from AIJ, but stores some additional
143    information that is used to allow better vectorization of
144    the matrix-vector product. At the cost of increased storage, the AIJ formatted
145    matrix can be copied to a format in which pieces of the matrix are
146    stored in ELLPACK format, allowing the vectorized matrix multiply
147    routine to use stride-1 memory accesses.  As with the AIJ type, it is
148    important to preallocate matrix storage in order to get good assembly
149    performance.
150 
151    Collective
152 
153    Input Parameters:
154 +  comm - MPI communicator, set to PETSC_COMM_SELF
155 .  m - number of rows
156 .  n - number of columns
157 .  nz - number of nonzeros per row (same for all rows)
158 -  nnz - array containing the number of nonzeros in the various rows
159          (possibly different for each row) or NULL
160 
161    Output Parameter:
162 .  A - the matrix
163 
164    Notes:
165    If nnz is given then nz is ignored
166 
167    Level: intermediate
168 
169 .seealso: `MatCreate()`, `MatCreateMPIAIJPERM()`, `MatSetValues()`
170 @*/
171 PetscErrorCode  MatCreateMPIAIJCRL(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt nz,const PetscInt nnz[],PetscInt onz,const PetscInt onnz[],Mat *A)
172 {
173   PetscFunctionBegin;
174   PetscCall(MatCreate(comm,A));
175   PetscCall(MatSetSizes(*A,m,n,m,n));
176   PetscCall(MatSetType(*A,MATMPIAIJCRL));
177   PetscCall(MatMPIAIJSetPreallocation_MPIAIJ(*A,nz,(PetscInt*)nnz,onz,(PetscInt*)onnz));
178   PetscFunctionReturn(0);
179 }
180 
181 PETSC_EXTERN PetscErrorCode MatCreate_MPIAIJCRL(Mat A)
182 {
183   PetscFunctionBegin;
184   PetscCall(MatSetType(A,MATMPIAIJ));
185   PetscCall(MatConvert_MPIAIJ_MPIAIJCRL(A,MATMPIAIJCRL,MAT_INPLACE_MATRIX,&A));
186   PetscFunctionReturn(0);
187 }
188