xref: /petsc/src/mat/impls/aij/seq/crl/crl.c (revision bcee047adeeb73090d7e36cc71e39fc287cdbb97)
1 
2 /*
3   Defines a matrix-vector product for the MATSEQAIJCRL matrix class.
4   This class is derived from the MATSEQAIJ 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 #include <../src/mat/impls/aij/seq/crl/crl.h>
13 
14 PetscErrorCode MatDestroy_SeqAIJCRL(Mat A)
15 {
16   Mat_AIJCRL *aijcrl = (Mat_AIJCRL *)A->spptr;
17 
18   PetscFunctionBegin;
19   /* Free everything in the Mat_AIJCRL data structure. */
20   if (aijcrl) PetscCall(PetscFree2(aijcrl->acols, aijcrl->icols));
21   PetscCall(PetscFree(A->spptr));
22   PetscCall(PetscObjectChangeTypeName((PetscObject)A, MATSEQAIJ));
23   PetscCall(MatDestroy_SeqAIJ(A));
24   PetscFunctionReturn(PETSC_SUCCESS);
25 }
26 
27 PetscErrorCode MatDuplicate_AIJCRL(Mat A, MatDuplicateOption op, Mat *M)
28 {
29   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Cannot duplicate AIJCRL matrices yet");
30 }
31 
32 PetscErrorCode MatSeqAIJCRL_create_aijcrl(Mat A)
33 {
34   Mat_SeqAIJ  *a      = (Mat_SeqAIJ *)(A)->data;
35   Mat_AIJCRL  *aijcrl = (Mat_AIJCRL *)A->spptr;
36   PetscInt     m      = A->rmap->n; /* Number of rows in the matrix. */
37   PetscInt    *aj     = a->j;       /* From the CSR representation; points to the beginning  of each row. */
38   PetscInt     i, j, rmax = a->rmax, *icols, *ilen = a->ilen;
39   MatScalar   *aa = a->a;
40   PetscScalar *acols;
41 
42   PetscFunctionBegin;
43   aijcrl->nz   = a->nz;
44   aijcrl->m    = A->rmap->n;
45   aijcrl->rmax = rmax;
46 
47   PetscCall(PetscFree2(aijcrl->acols, aijcrl->icols));
48   PetscCall(PetscMalloc2(rmax * m, &aijcrl->acols, rmax * m, &aijcrl->icols));
49   acols = aijcrl->acols;
50   icols = aijcrl->icols;
51   for (i = 0; i < m; i++) {
52     for (j = 0; j < ilen[i]; j++) {
53       acols[j * m + i] = *aa++;
54       icols[j * m + i] = *aj++;
55     }
56     for (; j < rmax; j++) { /* empty column entries */
57       acols[j * m + i] = 0.0;
58       icols[j * m + i] = (j) ? icols[(j - 1) * m + i] : 0; /* handle case where row is EMPTY */
59     }
60   }
61   PetscCall(PetscInfo(A, "Percentage of 0's introduced for vectorized multiply %g. Rmax= %" PetscInt_FMT "\n", 1.0 - ((double)a->nz) / ((double)(rmax * m)), rmax));
62   PetscFunctionReturn(PETSC_SUCCESS);
63 }
64 
65 PetscErrorCode MatAssemblyEnd_SeqAIJCRL(Mat A, MatAssemblyType mode)
66 {
67   Mat_SeqAIJ *a = (Mat_SeqAIJ *)A->data;
68 
69   PetscFunctionBegin;
70   a->inode.use = PETSC_FALSE;
71 
72   PetscCall(MatAssemblyEnd_SeqAIJ(A, mode));
73   if (mode == MAT_FLUSH_ASSEMBLY) PetscFunctionReturn(PETSC_SUCCESS);
74 
75   /* Now calculate the permutation and grouping information. */
76   PetscCall(MatSeqAIJCRL_create_aijcrl(A));
77   PetscFunctionReturn(PETSC_SUCCESS);
78 }
79 
80 #include <../src/mat/impls/aij/seq/crl/ftn-kernels/fmultcrl.h>
81 
82 /*
83     Shared by both sequential and parallel versions of CRL matrix: MATMPIAIJCRL and MATSEQAIJCRL
84     - the scatter is used only in the parallel version
85 
86 */
87 PetscErrorCode MatMult_AIJCRL(Mat A, Vec xx, Vec yy)
88 {
89   Mat_AIJCRL        *aijcrl = (Mat_AIJCRL *)A->spptr;
90   PetscInt           m      = aijcrl->m; /* Number of rows in the matrix. */
91   PetscInt           rmax = aijcrl->rmax, *icols = aijcrl->icols;
92   PetscScalar       *acols = aijcrl->acols;
93   PetscScalar       *y;
94   const PetscScalar *x;
95 #if !defined(PETSC_USE_FORTRAN_KERNEL_MULTCRL)
96   PetscInt i, j, ii;
97 #endif
98 
99 #if defined(PETSC_HAVE_PRAGMA_DISJOINT)
100   #pragma disjoint(*x, *y, *aa)
101 #endif
102 
103   PetscFunctionBegin;
104   if (aijcrl->xscat) {
105     PetscCall(VecCopy(xx, aijcrl->xwork));
106     /* get remote values needed for local part of multiply */
107     PetscCall(VecScatterBegin(aijcrl->xscat, xx, aijcrl->fwork, INSERT_VALUES, SCATTER_FORWARD));
108     PetscCall(VecScatterEnd(aijcrl->xscat, xx, aijcrl->fwork, INSERT_VALUES, SCATTER_FORWARD));
109     xx = aijcrl->xwork;
110   }
111 
112   PetscCall(VecGetArrayRead(xx, &x));
113   PetscCall(VecGetArray(yy, &y));
114 
115 #if defined(PETSC_USE_FORTRAN_KERNEL_MULTCRL)
116   fortranmultcrl_(&m, &rmax, x, y, icols, acols);
117 #else
118 
119   /* first column */
120   for (j = 0; j < m; j++) y[j] = acols[j] * x[icols[j]];
121 
122     /* other columns */
123   #if defined(PETSC_HAVE_CRAY_VECTOR)
124     #pragma _CRI preferstream
125   #endif
126   for (i = 1; i < rmax; i++) {
127     ii = i * m;
128   #if defined(PETSC_HAVE_CRAY_VECTOR)
129     #pragma _CRI prefervector
130   #endif
131     for (j = 0; j < m; j++) y[j] = y[j] + acols[ii + j] * x[icols[ii + j]];
132   }
133 #endif
134   PetscCall(PetscLogFlops(2.0 * aijcrl->nz - m));
135   PetscCall(VecRestoreArrayRead(xx, &x));
136   PetscCall(VecRestoreArray(yy, &y));
137   PetscFunctionReturn(PETSC_SUCCESS);
138 }
139 
140 /* MatConvert_SeqAIJ_SeqAIJCRL converts a SeqAIJ matrix into a
141  * SeqAIJCRL matrix.  This routine is called by the MatCreate_SeqAIJCRL()
142  * routine, but can also be used to convert an assembled SeqAIJ matrix
143  * into a SeqAIJCRL one. */
144 PETSC_INTERN PetscErrorCode MatConvert_SeqAIJ_SeqAIJCRL(Mat A, MatType type, MatReuse reuse, Mat *newmat)
145 {
146   Mat         B = *newmat;
147   Mat_AIJCRL *aijcrl;
148   PetscBool   sametype;
149 
150   PetscFunctionBegin;
151   if (reuse == MAT_INITIAL_MATRIX) PetscCall(MatDuplicate(A, MAT_COPY_VALUES, &B));
152   PetscCall(PetscObjectTypeCompare((PetscObject)A, type, &sametype));
153   if (sametype) PetscFunctionReturn(PETSC_SUCCESS);
154 
155   PetscCall(PetscNew(&aijcrl));
156   B->spptr = (void *)aijcrl;
157 
158   /* Set function pointers for methods that we inherit from AIJ but override. */
159   B->ops->duplicate   = MatDuplicate_AIJCRL;
160   B->ops->assemblyend = MatAssemblyEnd_SeqAIJCRL;
161   B->ops->destroy     = MatDestroy_SeqAIJCRL;
162   B->ops->mult        = MatMult_AIJCRL;
163 
164   /* If A has already been assembled, compute the permutation. */
165   if (A->assembled) PetscCall(MatSeqAIJCRL_create_aijcrl(B));
166   PetscCall(PetscObjectChangeTypeName((PetscObject)B, MATSEQAIJCRL));
167   *newmat = B;
168   PetscFunctionReturn(PETSC_SUCCESS);
169 }
170 
171 /*@C
172    MatCreateSeqAIJCRL - Creates a sparse matrix of type `MATSEQAIJCRL`.
173    This type inherits from `MATSEQAIJ`, but stores some additional
174    information that is used to allow better vectorization of
175    the matrix-vector product. At the cost of increased storage, the `MATSEQAIJ` formatted
176    matrix can be copied to a format in which pieces of the matrix are
177    stored in ELLPACK format, allowing the vectorized matrix multiply
178    routine to use stride-1 memory accesses.
179 
180    Collective
181 
182    Input Parameters:
183 +  comm - MPI communicator, set to `PETSC_COMM_SELF`
184 .  m - number of rows
185 .  n - number of columns
186 .  nz - number of nonzeros per row (same for all rows), ignored if `nnz` is given
187 -  nnz - array containing the number of nonzeros in the various rows
188          (possibly different for each row) or `NULL`
189 
190    Output Parameter:
191 .  A - the matrix
192 
193    Level: intermediate
194 
195 .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatCreateMPIAIJPERM()`, `MatSetValues()`
196 @*/
197 PetscErrorCode MatCreateSeqAIJCRL(MPI_Comm comm, PetscInt m, PetscInt n, PetscInt nz, const PetscInt nnz[], Mat *A)
198 {
199   PetscFunctionBegin;
200   PetscCall(MatCreate(comm, A));
201   PetscCall(MatSetSizes(*A, m, n, m, n));
202   PetscCall(MatSetType(*A, MATSEQAIJCRL));
203   PetscCall(MatSeqAIJSetPreallocation_SeqAIJ(*A, nz, nnz));
204   PetscFunctionReturn(PETSC_SUCCESS);
205 }
206 
207 PETSC_EXTERN PetscErrorCode MatCreate_SeqAIJCRL(Mat A)
208 {
209   PetscFunctionBegin;
210   PetscCall(MatSetType(A, MATSEQAIJ));
211   PetscCall(MatConvert_SeqAIJ_SeqAIJCRL(A, MATSEQAIJCRL, MAT_INPLACE_MATRIX, &A));
212   PetscFunctionReturn(PETSC_SUCCESS);
213 }
214