xref: /petsc/src/mat/tutorials/ex9.c (revision 1bb3edfd3d106a9ce6e99783e45c9200c8e18d90)
1 
2 static char help[] = "Tests MatCreateComposite()\n\n";
3 
4 /*
5   Include "petscmat.h" so that we can use matrices.
6   automatically includes:
7      petscsys.h       - base PETSc routines   petscvec.h    - vectors
8      petscmat.h    - matrices
9      petscis.h     - index sets            petscviewer.h - viewers
10 */
11 #include <petscmat.h>
12 
13 int main(int argc,char **args)
14 {
15   Mat              *A,B;           /* matrix */
16   Vec              x,y,v,v2,z,z2;
17   PetscReal        rnorm;
18   PetscInt         n = 20;         /* size of the matrix */
19   PetscInt         nmat = 3;       /* number of matrices */
20   PetscInt         i;
21   PetscRandom      rctx;
22   MatCompositeType type;
23   PetscScalar      scalings[5]={2,3,4,5,6};
24 
25   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
26   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
27   PetscCall(PetscOptionsGetInt(NULL,NULL,"-nmat",&nmat,NULL));
28 
29   /*
30      Create random matrices
31   */
32   PetscCall(PetscMalloc1(nmat+3,&A));
33   PetscCall(PetscRandomCreate(PETSC_COMM_WORLD,&rctx));
34   PetscCall(MatCreateAIJ(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,n,n/2,3,NULL,3,NULL,&A[0]));
35   for (i = 1; i < nmat+1; i++) {
36     PetscCall(MatCreateAIJ(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,n,n,3,NULL,3,NULL,&A[i]));
37   }
38   PetscCall(MatCreateAIJ(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,n/2,n,3,NULL,3,NULL,&A[nmat+1]));
39   for (i = 0; i < nmat+2; i++) {
40     PetscCall(MatSetRandom(A[i],rctx));
41   }
42 
43   PetscCall(MatCreateVecs(A[1],&x,&y));
44   PetscCall(VecDuplicate(y,&z));
45   PetscCall(VecDuplicate(z,&z2));
46   PetscCall(MatCreateVecs(A[0],&v,NULL));
47   PetscCall(VecDuplicate(v,&v2));
48 
49   /* Test MatMult of an ADDITIVE MatComposite B made up of A[1],A[2],A[3] with separate scalings */
50 
51   /* Do MatMult with A[1],A[2],A[3] by hand and store the result in z */
52   PetscCall(VecSet(x,1.0));
53   PetscCall(MatMult(A[1],x,z));
54   PetscCall(VecScale(z,scalings[1]));
55   for (i = 2; i < nmat+1; i++) {
56     PetscCall(MatMult(A[i],x,z2));
57     PetscCall(VecAXPY(z,scalings[i],z2));
58   }
59 
60   /* Do MatMult using MatComposite and store the result in y */
61   PetscCall(VecSet(y,0.0));
62   PetscCall(MatCreateComposite(PETSC_COMM_WORLD,nmat,A+1,&B));
63   PetscCall(MatSetFromOptions(B));
64   PetscCall(MatCompositeSetScalings(B,&scalings[1]));
65   PetscCall(MatMultAdd(B,x,y,y));
66 
67   /* Diff y and z */
68   PetscCall(VecAXPY(y,-1.0,z));
69   PetscCall(VecNorm(y,NORM_2,&rnorm));
70   if (rnorm > 10000.0*PETSC_MACHINE_EPSILON) {
71     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Error with composite add %g\n",(double)rnorm));
72   }
73 
74   /* Test MatCompositeMerge on ADDITIVE MatComposite */
75   PetscCall(MatCompositeSetMatStructure(B,DIFFERENT_NONZERO_PATTERN)); /* default */
76   PetscCall(MatCompositeMerge(B));
77   PetscCall(MatMult(B,x,y));
78   PetscCall(MatDestroy(&B));
79   PetscCall(VecAXPY(y,-1.0,z));
80   PetscCall(VecNorm(y,NORM_2,&rnorm));
81   if (rnorm > 10000.0*PETSC_MACHINE_EPSILON) {
82     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Error with composite add after merge %g\n",(double)rnorm));
83   }
84 
85   /*
86      Test n x n/2 multiplicative composite B made up of A[0],A[1],A[2] with separate scalings
87   */
88 
89   /* Do MatMult with A[0],A[1],A[2] by hand and store the result in z */
90   PetscCall(VecSet(v,1.0));
91   PetscCall(MatMult(A[0],v,z));
92   PetscCall(VecScale(z,scalings[0]));
93   for (i = 1; i < nmat; i++) {
94     PetscCall(MatMult(A[i],z,y));
95     PetscCall(VecScale(y,scalings[i]));
96     PetscCall(VecCopy(y,z));
97   }
98 
99   /* Do MatMult using MatComposite and store the result in y */
100   PetscCall(MatCreateComposite(PETSC_COMM_WORLD,nmat,A,&B));
101   PetscCall(MatCompositeSetType(B,MAT_COMPOSITE_MULTIPLICATIVE));
102   PetscCall(MatCompositeSetMergeType(B,MAT_COMPOSITE_MERGE_LEFT));
103   PetscCall(MatSetFromOptions(B));
104   PetscCall(MatCompositeSetScalings(B,&scalings[0]));
105   PetscCall(MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY));
106   PetscCall(MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY)); /* do MatCompositeMerge() if -mat_composite_merge 1 */
107   PetscCall(MatMult(B,v,y));
108   PetscCall(MatDestroy(&B));
109 
110   /* Diff y and z */
111   PetscCall(VecAXPY(y,-1.0,z));
112   PetscCall(VecNorm(y,NORM_2,&rnorm));
113   if (rnorm > 10000.0*PETSC_MACHINE_EPSILON) {
114     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Error with composite multiplicative %g\n",(double)rnorm));
115   }
116 
117   /*
118      Test n/2 x n multiplicative composite B made up of A[2], A[3], A[4] without separate scalings
119   */
120   PetscCall(VecSet(x,1.0));
121   PetscCall(MatMult(A[2],x,z));
122   for (i = 3; i < nmat+1; i++) {
123     PetscCall(MatMult(A[i],z,y));
124     PetscCall(VecCopy(y,z));
125   }
126   PetscCall(MatMult(A[nmat+1],z,v));
127 
128   PetscCall(MatCreateComposite(PETSC_COMM_WORLD,nmat,A+2,&B));
129   PetscCall(MatCompositeSetType(B,MAT_COMPOSITE_MULTIPLICATIVE));
130   PetscCall(MatSetFromOptions(B));
131   PetscCall(MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY));
132   PetscCall(MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY)); /* do MatCompositeMerge() if -mat_composite_merge 1 */
133   PetscCall(MatMult(B,x,v2));
134   PetscCall(MatDestroy(&B));
135 
136   PetscCall(VecAXPY(v2,-1.0,v));
137   PetscCall(VecNorm(v2,NORM_2,&rnorm));
138   if (rnorm > 10000.0*PETSC_MACHINE_EPSILON) {
139     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Error with composite multiplicative %g\n",(double)rnorm));
140   }
141 
142   /*
143      Test get functions
144   */
145   PetscCall(MatCreateComposite(PETSC_COMM_WORLD,nmat,A,&B));
146   PetscCall(MatCompositeGetNumberMat(B,&n));
147   if (nmat != n) {
148     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Error with GetNumberMat %" PetscInt_FMT " != %" PetscInt_FMT "\n",nmat,n));
149   }
150   PetscCall(MatCompositeGetMat(B,0,&A[nmat+2]));
151   if (A[0] != A[nmat+2]) {
152     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Error with GetMat\n"));
153   }
154   PetscCall(MatCompositeGetType(B,&type));
155   if (type != MAT_COMPOSITE_ADDITIVE) {
156     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Error with GetType\n"));
157   }
158   PetscCall(MatDestroy(&B));
159 
160   /*
161      Free work space.  All PETSc objects should be destroyed when they
162      are no longer needed.
163   */
164   PetscCall(VecDestroy(&x));
165   PetscCall(VecDestroy(&y));
166   PetscCall(VecDestroy(&v));
167   PetscCall(VecDestroy(&v2));
168   PetscCall(VecDestroy(&z));
169   PetscCall(VecDestroy(&z2));
170   PetscCall(PetscRandomDestroy(&rctx));
171   for (i = 0; i < nmat+2; i++) {
172     PetscCall(MatDestroy(&A[i]));
173   }
174   PetscCall(PetscFree(A));
175 
176   PetscCall(PetscFinalize());
177   return 0;
178 }
179 
180 /*TEST
181 
182    test:
183       nsize: 2
184       requires: double
185       args: -mat_composite_merge {{0 1}shared output} -mat_composite_merge_mvctx {{0 1}shared output}
186 
187 TEST*/
188