Date: 2022-08-02T03:14:08+00:00

Actual source code: ex2.c

      1: static char help[] = "testing SeqDense matrices with an LDA (leading dimension of the user-allocated array) larger than M.\n";
      2: /*
      3:  * Example code testing SeqDense matrices with an LDA (leading dimension
      4:  * of the user-allocated array) larger than M.
      5:  * This example tests the functionality of MatSetValues(), MatMult(),
      6:  * and MatMultTranspose().
      7:  */

      9: #include <petscmat.h>

     11: int main(int argc,char **argv)
     12: {
     13:   Mat            A,A11,A12,A21,A22;
     14:   Vec            X,X1,X2,Y,Z,Z1,Z2;
     15:   PetscScalar    *a,*b,*x,*y,*z,v,one=1;
     16:   PetscReal      nrm;
     17:   PetscInt       size=8,size1=6,size2=2, i,j;
     18:   PetscRandom    rnd;

     20:   PetscInitialize(&argc,&argv,0,help);
     21:   PetscRandomCreate(PETSC_COMM_SELF,&rnd);

     23:   /*
     24:    * Create matrix and three vectors: these are all normal
     25:    */
     26:   PetscMalloc1(size*size,&a);
     27:   PetscMalloc1(size*size,&b);
     28:   for (i=0; i<size; i++) {
     29:     for (j=0; j<size; j++) {
     30:       PetscRandomGetValue(rnd,&a[i+j*size]);
     31:       b[i+j*size] = a[i+j*size];
     32:     }
     33:   }
     34:   MatCreate(PETSC_COMM_SELF,&A);
     35:   MatSetSizes(A,size,size,size,size);
     36:   MatSetType(A,MATSEQDENSE);
     37:   MatSeqDenseSetPreallocation(A,a);
     38:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     39:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

     41:   PetscMalloc1(size,&x);
     42:   for (i=0; i<size; i++) {
     43:     x[i] = one;
     44:   }
     45:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,size,x,&X);
     46:   VecAssemblyBegin(X);
     47:   VecAssemblyEnd(X);

     49:   PetscMalloc1(size,&y);
     50:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,size,y,&Y);
     51:   VecAssemblyBegin(Y);
     52:   VecAssemblyEnd(Y);

     54:   PetscMalloc1(size,&z);
     55:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,size,z,&Z);
     56:   VecAssemblyBegin(Z);
     57:   VecAssemblyEnd(Z);

     59:   /*
     60:    * Now create submatrices and subvectors
     61:    */
     62:   MatCreate(PETSC_COMM_SELF,&A11);
     63:   MatSetSizes(A11,size1,size1,size1,size1);
     64:   MatSetType(A11,MATSEQDENSE);
     65:   MatSeqDenseSetPreallocation(A11,b);
     66:   MatDenseSetLDA(A11,size);
     67:   MatAssemblyBegin(A11,MAT_FINAL_ASSEMBLY);
     68:   MatAssemblyEnd(A11,MAT_FINAL_ASSEMBLY);

     70:   MatCreate(PETSC_COMM_SELF,&A12);
     71:   MatSetSizes(A12,size1,size2,size1,size2);
     72:   MatSetType(A12,MATSEQDENSE);
     73:   MatSeqDenseSetPreallocation(A12,b+size1*size);
     74:   MatDenseSetLDA(A12,size);
     75:   MatAssemblyBegin(A12,MAT_FINAL_ASSEMBLY);
     76:   MatAssemblyEnd(A12,MAT_FINAL_ASSEMBLY);

     78:   MatCreate(PETSC_COMM_SELF,&A21);
     79:   MatSetSizes(A21,size2,size1,size2,size1);
     80:   MatSetType(A21,MATSEQDENSE);
     81:   MatSeqDenseSetPreallocation(A21,b+size1);
     82:   MatDenseSetLDA(A21,size);
     83:   MatAssemblyBegin(A21,MAT_FINAL_ASSEMBLY);
     84:   MatAssemblyEnd(A21,MAT_FINAL_ASSEMBLY);

     86:   MatCreate(PETSC_COMM_SELF,&A22);
     87:   MatSetSizes(A22,size2,size2,size2,size2);
     88:   MatSetType(A22,MATSEQDENSE);
     89:   MatSeqDenseSetPreallocation(A22,b+size1*size+size1);
     90:   MatDenseSetLDA(A22,size);
     91:   MatAssemblyBegin(A22,MAT_FINAL_ASSEMBLY);
     92:   MatAssemblyEnd(A22,MAT_FINAL_ASSEMBLY);

     94:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,size1,x,&X1);
     95:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,size2,x+size1,&X2);
     96:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,size1,z,&Z1);
     97:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,size2,z+size1,&Z2);

     99:   /*
    100:    * Now multiple matrix times input in two ways;
    101:    * compare the results
    102:    */
    103:   MatMult(A,X,Y);
    104:   MatMult(A11,X1,Z1);
    105:   MatMultAdd(A12,X2,Z1,Z1);
    106:   MatMult(A22,X2,Z2);
    107:   MatMultAdd(A21,X1,Z2,Z2);
    108:   VecAXPY(Z,-1.0,Y);
    109:   VecNorm(Z,NORM_2,&nrm);
    110:   if (nrm > 100.0*PETSC_MACHINE_EPSILON) {
    111:     PetscPrintf(PETSC_COMM_WORLD,"Test1; error norm=%g\n",(double)nrm);
    112:   }

    114:   /*
    115:    * Next test: change both matrices
    116:    */
    117:   PetscRandomGetValue(rnd,&v);
    118:   i    = 1;
    119:   j    = size-2;
    120:   MatSetValues(A,1,&i,1,&j,&v,INSERT_VALUES);
    121:   j   -= size1;
    122:   MatSetValues(A12,1,&i,1,&j,&v,INSERT_VALUES);
    123:   PetscRandomGetValue(rnd,&v);
    124:   i    = j = size1+1;
    125:   MatSetValues(A,1,&i,1,&j,&v,INSERT_VALUES);
    126:   i     =j = 1;
    127:   MatSetValues(A22,1,&i,1,&j,&v,INSERT_VALUES);
    128:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
    129:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
    130:   MatAssemblyBegin(A12,MAT_FINAL_ASSEMBLY);
    131:   MatAssemblyEnd(A12,MAT_FINAL_ASSEMBLY);
    132:   MatAssemblyBegin(A22,MAT_FINAL_ASSEMBLY);
    133:   MatAssemblyEnd(A22,MAT_FINAL_ASSEMBLY);

    135:   MatMult(A,X,Y);
    136:   MatMult(A11,X1,Z1);
    137:   MatMultAdd(A12,X2,Z1,Z1);
    138:   MatMult(A22,X2,Z2);
    139:   MatMultAdd(A21,X1,Z2,Z2);
    140:   VecAXPY(Z,-1.0,Y);
    141:   VecNorm(Z,NORM_2,&nrm);
    142:   if (nrm > 100.0*PETSC_MACHINE_EPSILON) {
    143:     PetscPrintf(PETSC_COMM_WORLD,"Test2; error norm=%g\n",(double)nrm);
    144:   }

    146:   /*
    147:    * Transpose product
    148:    */
    149:   MatMultTranspose(A,X,Y);
    150:   MatMultTranspose(A11,X1,Z1);
    151:   MatMultTransposeAdd(A21,X2,Z1,Z1);
    152:   MatMultTranspose(A22,X2,Z2);
    153:   MatMultTransposeAdd(A12,X1,Z2,Z2);
    154:   VecAXPY(Z,-1.0,Y);
    155:   VecNorm(Z,NORM_2,&nrm);
    156:   if (nrm > 100.0*PETSC_MACHINE_EPSILON) {
    157:     PetscPrintf(PETSC_COMM_WORLD,"Test3; error norm=%g\n",(double)nrm);
    158:   }
    159:   PetscFree(a);
    160:   PetscFree(b);
    161:   PetscFree(x);
    162:   PetscFree(y);
    163:   PetscFree(z);
    164:   MatDestroy(&A);
    165:   MatDestroy(&A11);
    166:   MatDestroy(&A12);
    167:   MatDestroy(&A21);
    168:   MatDestroy(&A22);

    170:   VecDestroy(&X);
    171:   VecDestroy(&Y);
    172:   VecDestroy(&Z);

    174:   VecDestroy(&X1);
    175:   VecDestroy(&X2);
    176:   VecDestroy(&Z1);
    177:   VecDestroy(&Z2);
    178:   PetscRandomDestroy(&rnd);
    179:   PetscFinalize();
    180:   return 0;
    181: }

    183: /*TEST

    185:    test:

    187: TEST*/