Actual source code: ex195.c

  1: /*
  2:  * ex195.c
  3:  *
  4:  *  Created on: Aug 24, 2015
  5:  *      Author: Fande Kong <fdkong.jd@gmail.com>
  6:  */

  8: static char help[] = " Demonstrate the use of MatConvert_Nest_AIJ\n";

 10: #include <petscmat.h>

 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;

 23:   PetscFunctionBeginUser;
 24:   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
 25:   comm = PETSC_COMM_WORLD;
 26:   PetscCallMPI(MPI_Comm_size(comm, &size));

 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));

 64:   PetscCall(MatDuplicate(A1, MAT_COPY_VALUES, &A2));
 65:   PetscCall(MatDuplicate(A1, MAT_COPY_VALUES, &A3));
 66:   PetscCall(MatDuplicate(A1, MAT_COPY_VALUES, &A4));

 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));

 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));

 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");

 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));

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));

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:   }

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: }

132: /*TEST

134:    test:
135:       nsize: 2

137:    test:
138:       suffix: 2

140: TEST*/