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

 27:   /*
 28:      Assemble the matrix for the five point stencil, YET AGAIN
 29:   */
 30:   MatCreate(comm,&A1);
 31:   m=2,n=2;
 32:   MatSetSizes(A1,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);
 33:   MatSetFromOptions(A1);
 34:   MatSetUp(A1);
 35:   MatGetOwnershipRange(A1,&istart,&iend);
 36:   for (ii=istart; ii<iend; ii++) {
 37:     v = -1.0; i = ii/n; j = ii - i*n;
 38:     if (i>0)   {J = ii - n; MatSetValues(A1,1,&ii,1,&J,&v,INSERT_VALUES);}
 39:     if (i<m-1) {J = ii + n; MatSetValues(A1,1,&ii,1,&J,&v,INSERT_VALUES);}
 40:     if (j>0)   {J = ii - 1; MatSetValues(A1,1,&ii,1,&J,&v,INSERT_VALUES);}
 41:     if (j<n-1) {J = ii + 1; MatSetValues(A1,1,&ii,1,&J,&v,INSERT_VALUES);}
 42:     v = 4.0; MatSetValues(A1,1,&ii,1,&ii,&v,INSERT_VALUES);
 43:   }
 44:   MatAssemblyBegin(A1,MAT_FINAL_ASSEMBLY);
 45:   MatAssemblyEnd(A1,MAT_FINAL_ASSEMBLY);
 46:   MatView(A1,PETSC_VIEWER_STDOUT_WORLD);

 48:   MatDuplicate(A1,MAT_COPY_VALUES,&A2);
 49:   MatDuplicate(A1,MAT_COPY_VALUES,&A3);
 50:   MatDuplicate(A1,MAT_COPY_VALUES,&A4);

 52:   /*create a nest matrix */
 53:   MatCreate(comm,&nest);
 54:   MatSetType(nest,MATNEST);
 55:   mata[0]=A1,mata[1]=A2,mata[2]=A3,mata[3]=A4;
 56:   MatNestSetSubMats(nest,2,NULL,2,NULL,mata);
 57:   MatSetUp(nest);
 58:   MatConvert(nest,MATAIJ,MAT_INITIAL_MATRIX,&aij);
 59:   MatView(aij,PETSC_VIEWER_STDOUT_WORLD);

 61:   /* create a dense matrix */
 62:   MatGetSize(nest,&M,NULL);
 63:   MatGetLocalSize(nest,&m,NULL);
 64:   MatCreateDense(comm,m,PETSC_DECIDE,M,K,NULL,&B);
 65:   MatSetRandom(B,PETSC_NULL);
 66:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
 67:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);

 69:   /* C = nest*B_dense */
 70:   MatMatMult(nest,B,MAT_INITIAL_MATRIX,PETSC_DEFAULT,&C);
 71:   MatMatMult(nest,B,MAT_REUSE_MATRIX,PETSC_DEFAULT,&C);
 72:   MatMatMultEqual(nest,B,C,10,&equal);

 75:   /* Test B = nest*C, reuse C and B with MatProductCreateWithMat() */
 76:   /* C has been obtained from nest*B. Clear internal data structures related to factors to prevent circular references */
 77:   MatProductClear(C);
 78:   MatProductCreateWithMat(nest,C,NULL,B);
 79:   MatProductSetType(B,MATPRODUCT_AB);
 80:   MatProductSetFromOptions(B);
 81:   MatProductSymbolic(B);
 82:   MatProductNumeric(B);
 83:   MatMatMultEqual(nest,C,B,10,&equal);
 85:   MatConvert(nest,MATAIJ,MAT_INPLACE_MATRIX,&nest);
 86:   MatEqual(nest,aij,&equal);
 88:   MatDestroy(&nest);

 90:   if (size > 1) { /* Do not know why this test fails for size = 1 */
 91:     MatCreateTranspose(A1,&A5); /* A1 is symmetric */
 92:     mata[0] = A5;
 93:     MatCreate(comm,&nest);
 94:     MatSetType(nest,MATNEST);
 95:     MatNestSetSubMats(nest,2,NULL,2,NULL,mata);
 96:     MatSetUp(nest);
 97:     MatMatMult(nest,B,MAT_INITIAL_MATRIX,PETSC_DEFAULT,&C1);
 98:     MatMatMult(nest,B,MAT_REUSE_MATRIX,PETSC_DEFAULT,&C1);

100:     MatMatMultEqual(nest,B,C1,10,&equal);
102:     MatDestroy(&C1);
103:     MatDestroy(&A5);
104:     MatDestroy(&nest);
105:   }

107:   MatDestroy(&C);
108:   MatDestroy(&B);
109:   MatDestroy(&aij);
110:   MatDestroy(&A1);
111:   MatDestroy(&A2);
112:   MatDestroy(&A3);
113:   MatDestroy(&A4);
114:   PetscFinalize();
115:   return 0;
116: }

118: /*TEST

120:    test:
121:       nsize: 2

123:    test:
124:       suffix: 2

126: TEST*/