Actual source code: ex178.c


  2: static char help[] = "Tests MatInvertVariableBlockEnvelope()\n\n";

  4: #include <petscmat.h>
  5: extern PetscErrorCode MatIsDiagonal(Mat);
  6: extern PetscErrorCode BuildMatrix(const PetscInt *, PetscInt, const PetscInt *, Mat *);

  8: int main(int argc, char **argv)
  9: {
 10:   Mat         A, C, D, F;
 11:   PetscInt    i, j, rows[2], *parts, cnt, N = 21, nblocks, *blocksizes;
 12:   PetscScalar values[2][2];
 13:   PetscReal   rand;
 14:   PetscRandom rctx;
 15:   PetscMPIInt size;

 18:   PetscInitialize(&argc, &argv, (char *)0, help);
 19:   PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_DENSE);

 21:   MatCreate(PETSC_COMM_WORLD, &C);
 22:   MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, 6, 18);
 23:   MatSetFromOptions(C);
 24:   MatSetUp(C);
 25:   values[0][0] = 2;
 26:   values[0][1] = 1;
 27:   values[1][0] = 1;
 28:   values[1][1] = 2;
 29:   for (i = 0; i < 3; i++) {
 30:     rows[0] = 2 * i;
 31:     rows[1] = 2 * i + 1;
 32:     MatSetValues(C, 2, rows, 2, rows, (PetscScalar *)values, INSERT_VALUES);
 33:   }
 34:   MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY);
 35:   MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY);
 36:   MatView(C, PETSC_VIEWER_STDOUT_WORLD);

 38:   MatMatTransposeMult(C, C, MAT_INITIAL_MATRIX, PETSC_DETERMINE, &A);
 39:   MatView(A, PETSC_VIEWER_STDOUT_WORLD);

 41:   MatInvertVariableBlockEnvelope(A, MAT_INITIAL_MATRIX, &D);
 42:   MatView(D, PETSC_VIEWER_STDOUT_WORLD);

 44:   MatMatMult(A, D, MAT_INITIAL_MATRIX, 1.0, &F);
 45:   MatView(F, PETSC_VIEWER_STDOUT_WORLD);
 46:   MatIsDiagonal(F);

 48:   MatDestroy(&A);
 49:   MatDestroy(&D);
 50:   MatDestroy(&C);
 51:   MatDestroy(&F);

 53:   PetscRandomCreate(PETSC_COMM_SELF, &rctx);
 54:   MPI_Comm_size(PETSC_COMM_WORLD, &size);
 55:   PetscMalloc1(size, &parts);

 57:   for (j = 0; j < 128; j++) {
 58:     cnt = 0;
 59:     for (i = 0; i < size - 1; i++) {
 60:       PetscRandomGetValueReal(rctx, &rand);
 61:       parts[i] = (PetscInt)N * rand;
 62:       parts[i] = PetscMin(parts[i], N - cnt);
 63:       cnt += parts[i];
 64:     }
 65:     parts[size - 1] = N - cnt;

 67:     PetscRandomGetValueReal(rctx, &rand);
 68:     nblocks = rand * 10;
 69:     nblocks = PetscMax(nblocks, 2);
 70:     cnt     = 0;
 71:     PetscMalloc1(nblocks, &blocksizes);
 72:     for (i = 0; i < nblocks - 1; i++) {
 73:       PetscRandomGetValueReal(rctx, &rand);
 74:       blocksizes[i] = PetscMax(1, (PetscInt)N * rand);
 75:       blocksizes[i] = PetscMin(blocksizes[i], N - cnt);
 76:       cnt += blocksizes[i];
 77:       if (cnt == N) {
 78:         nblocks = i + 1;
 79:         break;
 80:       }
 81:     }
 82:     if (cnt < N) blocksizes[nblocks - 1] = N - cnt;

 84:     BuildMatrix(parts, nblocks, blocksizes, &A);
 85:     PetscFree(blocksizes);

 87:     MatInvertVariableBlockEnvelope(A, MAT_INITIAL_MATRIX, &D);

 89:     MatMatMult(A, D, MAT_INITIAL_MATRIX, 1.0, &F);
 90:     MatIsDiagonal(F);

 92:     MatDestroy(&A);
 93:     MatDestroy(&D);
 94:     MatDestroy(&F);
 95:   }
 96:   PetscFree(parts);
 97:   PetscRandomDestroy(&rctx);

 99:   PetscFinalize();
100:   return 0;
101: }

103: PetscErrorCode MatIsDiagonal(Mat A)
104: {
105:   PetscInt           ncols, i, j, rstart, rend;
106:   const PetscInt    *cols;
107:   const PetscScalar *vals;
108:   PetscBool          founddiag;

111:   MatGetOwnershipRange(A, &rstart, &rend);
112:   for (i = rstart; i < rend; i++) {
113:     founddiag = PETSC_FALSE;
114:     MatGetRow(A, i, &ncols, &cols, &vals);
115:     for (j = 0; j < ncols; j++) {
116:       if (cols[j] == i) {
118:         founddiag = PETSC_TRUE;
119:       } else {
121:       }
122:     }
123:     MatRestoreRow(A, i, &ncols, &cols, &vals);
125:   }
126:   return 0;
127: }

129: /*
130:     All processes receive all the block information
131: */
132: PetscErrorCode BuildMatrix(const PetscInt *parts, PetscInt nblocks, const PetscInt *blocksizes, Mat *A)
133: {
134:   PetscInt    i, cnt = 0;
135:   PetscMPIInt rank;

138:   MPI_Comm_rank(PETSC_COMM_WORLD, &rank);
139:   MatCreateAIJ(PETSC_COMM_WORLD, parts[rank], parts[rank], PETSC_DETERMINE, PETSC_DETERMINE, 0, NULL, 0, NULL, A);
140:   MatSetOption(*A, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE);
141:   if (rank == 0) {
142:     for (i = 0; i < nblocks; i++) {
143:       MatSetValue(*A, cnt, cnt + blocksizes[i] - 1, 1.0, INSERT_VALUES);
144:       MatSetValue(*A, cnt + blocksizes[i] - 1, cnt, 1.0, INSERT_VALUES);
145:       cnt += blocksizes[i];
146:     }
147:   }
148:   MatAssemblyBegin(*A, MAT_FINAL_ASSEMBLY);
149:   MatAssemblyEnd(*A, MAT_FINAL_ASSEMBLY);
150:   MatShift(*A, 10);
151:   return 0;
152: }

154: /*TEST

156:    test:

158:    test:
159:      suffix: 2
160:      nsize: 2

162:    test:
163:      suffix: 5
164:      nsize: 5

166: TEST*/