xref: /petsc/src/mat/tests/ex195.c (revision 21e3ffae2f3b73c0bd738cf6d0a809700fc04bb0)
1 /*
2  * ex195.c
3  *
4  *  Created on: Aug 24, 2015
5  *      Author: Fande Kong <fdkong.jd@gmail.com>
6  */
7 
8 static char help[] = " Demonstrate the use of MatConvert_Nest_AIJ\n";
9 
10 #include <petscmat.h>
11 
12 int main(int argc, char **args)
13 {
14   Mat         A1, A2, A3, A4, A5, B, C, C1, nest;
15   Mat         mata[4];
16   Mat         aij;
17   MPI_Comm    comm;
18   PetscInt    m, M, n, istart, iend, ii, i, J, j, K = 10;
19   PetscScalar v;
20   PetscMPIInt size;
21   PetscBool   equal;
22 
23   PetscFunctionBeginUser;
24   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
25   comm = PETSC_COMM_WORLD;
26   PetscCallMPI(MPI_Comm_size(comm, &size));
27 
28   /*
29      Assemble the matrix for the five point stencil, YET AGAIN
30   */
31   PetscCall(MatCreate(comm, &A1));
32   m = 2, n = 2;
33   PetscCall(MatSetSizes(A1, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
34   PetscCall(MatSetFromOptions(A1));
35   PetscCall(MatSetUp(A1));
36   PetscCall(MatGetOwnershipRange(A1, &istart, &iend));
37   for (ii = istart; ii < iend; ii++) {
38     v = -1.0;
39     i = ii / n;
40     j = ii - i * n;
41     if (i > 0) {
42       J = ii - n;
43       PetscCall(MatSetValues(A1, 1, &ii, 1, &J, &v, INSERT_VALUES));
44     }
45     if (i < m - 1) {
46       J = ii + n;
47       PetscCall(MatSetValues(A1, 1, &ii, 1, &J, &v, INSERT_VALUES));
48     }
49     if (j > 0) {
50       J = ii - 1;
51       PetscCall(MatSetValues(A1, 1, &ii, 1, &J, &v, INSERT_VALUES));
52     }
53     if (j < n - 1) {
54       J = ii + 1;
55       PetscCall(MatSetValues(A1, 1, &ii, 1, &J, &v, INSERT_VALUES));
56     }
57     v = 4.0;
58     PetscCall(MatSetValues(A1, 1, &ii, 1, &ii, &v, INSERT_VALUES));
59   }
60   PetscCall(MatAssemblyBegin(A1, MAT_FINAL_ASSEMBLY));
61   PetscCall(MatAssemblyEnd(A1, MAT_FINAL_ASSEMBLY));
62   PetscCall(MatView(A1, PETSC_VIEWER_STDOUT_WORLD));
63 
64   PetscCall(MatDuplicate(A1, MAT_COPY_VALUES, &A2));
65   PetscCall(MatDuplicate(A1, MAT_COPY_VALUES, &A3));
66   PetscCall(MatDuplicate(A1, MAT_COPY_VALUES, &A4));
67 
68   /*create a nest matrix */
69   PetscCall(MatCreate(comm, &nest));
70   PetscCall(MatSetType(nest, MATNEST));
71   mata[0] = A1, mata[1] = A2, mata[2] = A3, mata[3] = A4;
72   PetscCall(MatNestSetSubMats(nest, 2, NULL, 2, NULL, mata));
73   PetscCall(MatSetUp(nest));
74   PetscCall(MatConvert(nest, MATAIJ, MAT_INITIAL_MATRIX, &aij));
75   PetscCall(MatView(aij, PETSC_VIEWER_STDOUT_WORLD));
76 
77   /* create a dense matrix */
78   PetscCall(MatGetSize(nest, &M, NULL));
79   PetscCall(MatGetLocalSize(nest, &m, NULL));
80   PetscCall(MatCreateDense(comm, m, PETSC_DECIDE, M, K, NULL, &B));
81   PetscCall(MatSetRandom(B, NULL));
82 
83   /* C = nest*B_dense */
84   PetscCall(MatMatMult(nest, B, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &C));
85   PetscCall(MatMatMult(nest, B, MAT_REUSE_MATRIX, PETSC_DEFAULT, &C));
86   PetscCall(MatMatMultEqual(nest, B, C, 10, &equal));
87   PetscCheck(equal, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Error in C != nest*B_dense");
88 
89   /* Test B = nest*C, reuse C and B with MatProductCreateWithMat() */
90   /* C has been obtained from nest*B. Clear internal data structures related to factors to prevent circular references */
91   PetscCall(MatProductClear(C));
92   PetscCall(MatProductCreateWithMat(nest, C, NULL, B));
93   PetscCall(MatProductSetType(B, MATPRODUCT_AB));
94   PetscCall(MatProductSetFromOptions(B));
95   PetscCall(MatProductSymbolic(B));
96   PetscCall(MatProductNumeric(B));
97   PetscCall(MatMatMultEqual(nest, C, B, 10, &equal));
98   PetscCheck(equal, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Error in B != nest*C_dense");
99   PetscCall(MatConvert(nest, MATAIJ, MAT_INPLACE_MATRIX, &nest));
100   PetscCall(MatEqual(nest, aij, &equal));
101   PetscCheck(equal, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Error in aij != nest");
102   PetscCall(MatDestroy(&nest));
103 
104   if (size > 1) {                           /* Do not know why this test fails for size = 1 */
105     PetscCall(MatCreateTranspose(A1, &A5)); /* A1 is symmetric */
106     mata[0] = A5;
107     PetscCall(MatCreate(comm, &nest));
108     PetscCall(MatSetType(nest, MATNEST));
109     PetscCall(MatNestSetSubMats(nest, 2, NULL, 2, NULL, mata));
110     PetscCall(MatSetUp(nest));
111     PetscCall(MatMatMult(nest, B, MAT_INITIAL_MATRIX, PETSC_DEFAULT, &C1));
112     PetscCall(MatMatMult(nest, B, MAT_REUSE_MATRIX, PETSC_DEFAULT, &C1));
113 
114     PetscCall(MatMatMultEqual(nest, B, C1, 10, &equal));
115     PetscCheck(equal, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Error in C1 != C");
116     PetscCall(MatDestroy(&C1));
117     PetscCall(MatDestroy(&A5));
118     PetscCall(MatDestroy(&nest));
119   }
120 
121   PetscCall(MatDestroy(&C));
122   PetscCall(MatDestroy(&B));
123   PetscCall(MatDestroy(&aij));
124   PetscCall(MatDestroy(&A1));
125   PetscCall(MatDestroy(&A2));
126   PetscCall(MatDestroy(&A3));
127   PetscCall(MatDestroy(&A4));
128   PetscCall(PetscFinalize());
129   return 0;
130 }
131 
132 /*TEST
133 
134    test:
135       nsize: 2
136 
137    test:
138       suffix: 2
139 
140 TEST*/
141