Actual source code: ex30.c

petsc-master 2017-08-19
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  1: static char help[] = " * Example code testing SeqDense matrices with an LDA (leading dimension of the user-allocated arrray) larger than M.\n";

  3:  #include <petscksp.h>

  5: int main(int argc,char **argv)
  6: {
  7:   KSP            solver;
  8:   PC             pc;
  9:   Mat            A,B;
 10:   Vec            X,Y,Z;
 11:   MatScalar      *a;
 12:   PetscScalar    *b,*x,*y,*z;
 13:   PetscReal      nrm;
 14:   PetscErrorCode ierr,size=8,lda=10, i,j;

 16:   PetscInitialize(&argc,&argv,0,help);if (ierr) return ierr;
 17:   /* Create matrix and three vectors: these are all normal */
 18:   PetscMalloc1(lda*size,&b);
 19:   for (i=0; i<size; i++) {
 20:     for (j=0; j<size; j++) {
 21:       b[i+j*lda] = rand();
 22:     }
 23:   }
 24:   MatCreate(MPI_COMM_SELF,&A);
 25:   MatSetSizes(A,size,size,size,size);
 26:   MatSetType(A,MATSEQDENSE);
 27:   MatSeqDenseSetPreallocation(A,NULL);

 29:   MatDenseGetArray(A,&a);
 30:   for (i=0; i<size; i++) {
 31:     for (j=0; j<size; j++) {
 32:       a[i+j*size] = b[i+j*lda];
 33:     }
 34:   }
 35:   MatDenseRestoreArray(A,&a);
 36:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 37:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 39:   MatCreate(MPI_COMM_SELF,&B);
 40:   MatSetSizes(B,size,size,size,size);
 41:   MatSetType(B,MATSEQDENSE);
 42:   MatSeqDenseSetPreallocation(B,b);
 43:   MatSeqDenseSetLDA(B,lda);
 44:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
 45:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);

 47:   PetscMalloc1(size,&x);
 48:   for (i=0; i<size; i++) x[i] = 1.0;
 49:   VecCreateSeqWithArray(MPI_COMM_SELF,1,size,x,&X);
 50:   VecAssemblyBegin(X);
 51:   VecAssemblyEnd(X);

 53:   PetscMalloc1(size,&y);
 54:   VecCreateSeqWithArray(MPI_COMM_SELF,1,size,y,&Y);
 55:   VecAssemblyBegin(Y);
 56:   VecAssemblyEnd(Y);

 58:   PetscMalloc1(size,&z);
 59:   VecCreateSeqWithArray(MPI_COMM_SELF,1,size,z,&Z);
 60:   VecAssemblyBegin(Z);
 61:   VecAssemblyEnd(Z);

 63:   /*
 64:    * Solve with A and B
 65:    */
 66:   KSPCreate(MPI_COMM_SELF,&solver);
 67:   KSPSetType(solver,KSPPREONLY);
 68:   KSPGetPC(solver,&pc);
 69:   PCSetType(pc,PCLU);
 70:   KSPSetOperators(solver,A,A);
 71:   KSPSolve(solver,X,Y);
 72:   KSPSetOperators(solver,B,B);
 73:   KSPSolve(solver,X,Z);
 74:   VecAXPY(Z,-1.0,Y);
 75:   VecNorm(Z,NORM_2,&nrm);
 76:   PetscPrintf(PETSC_COMM_SELF,"Test1; error norm=%e\n",nrm);

 78:   /* Free spaces */
 79:   PetscFree(b);
 80:   PetscFree(x);
 81:   PetscFree(y);
 82:   PetscFree(z);
 83:   VecDestroy(&X);
 84:   VecDestroy(&Y);
 85:   VecDestroy(&Z);
 86:   MatDestroy(&A);
 87:   MatDestroy(&B);
 88:   KSPDestroy(&solver);

 90:   PetscFinalize();
 91:   return ierr;
 92: }