Actual source code: ex6.c

petsc-3.12.0 2019-09-29
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  2: static char help[] = "Reads a PETSc matrix and vector from a file and solves a linear system.\n\
  3: Input arguments are:\n\
  4:   -f <input_file> : file to load. For example see $PETSC_DIR/share/petsc/datafiles/matrices\n\n";

  6:  #include <petscksp.h>
  7:  #include <petsclog.h>

  9: int main(int argc,char **args)
 10: {
 12:   PetscInt       its;
 13:   PetscLogStage  stage1,stage2;
 14:   PetscReal      norm;
 15:   Vec            x,b,u;
 16:   Mat            A;
 17:   char           file[PETSC_MAX_PATH_LEN];
 18:   PetscViewer    fd;
 19:   PetscBool      table = PETSC_FALSE,flg;
 20:   KSP            ksp;

 22:   PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
 23:   PetscOptionsGetBool(NULL,NULL,"-table",&table,NULL);

 25:   /* Read matrix and RHS */
 26:   PetscOptionsGetString(NULL,NULL,"-f",file,PETSC_MAX_PATH_LEN,&flg);
 27:   if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate binary file with the -f option");
 28:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);
 29:   MatCreate(PETSC_COMM_WORLD,&A);
 30:   MatLoad(A,fd);
 31:   VecCreate(PETSC_COMM_WORLD,&b);
 32:   VecLoad(b,fd);
 33:   PetscViewerDestroy(&fd);

 35:   /*
 36:    If the load matrix is larger then the vector, due to being padded
 37:    to match the blocksize then create a new padded vector
 38:   */
 39:   {
 40:     PetscInt    m,n,j,mvec,start,end,indx;
 41:     Vec         tmp;
 42:     PetscScalar *bold;

 44:     MatGetLocalSize(A,&m,&n);
 45:     VecCreate(PETSC_COMM_WORLD,&tmp);
 46:     VecSetSizes(tmp,m,PETSC_DECIDE);
 47:     VecSetFromOptions(tmp);
 48:     VecGetOwnershipRange(b,&start,&end);
 49:     VecGetLocalSize(b,&mvec);
 50:     VecGetArray(b,&bold);
 51:     for (j=0; j<mvec; j++) {
 52:       indx = start+j;
 53:       VecSetValues(tmp,1,&indx,bold+j,INSERT_VALUES);
 54:     }
 55:     VecRestoreArray(b,&bold);
 56:     VecDestroy(&b);
 57:     VecAssemblyBegin(tmp);
 58:     VecAssemblyEnd(tmp);
 59:     b    = tmp;
 60:   }
 61:   VecDuplicate(b,&x);
 62:   VecDuplicate(b,&u);

 64:   VecSet(x,0.0);
 65:   PetscBarrier((PetscObject)A);

 67:   PetscLogStageRegister("mystage 1",&stage1);
 68:   PetscLogStagePush(stage1);
 69:   KSPCreate(PETSC_COMM_WORLD,&ksp);
 70:   KSPSetOperators(ksp,A,A);
 71:   KSPSetFromOptions(ksp);
 72:   KSPSetUp(ksp);
 73:   KSPSetUpOnBlocks(ksp);
 74:   PetscLogStagePop();
 75:   PetscBarrier((PetscObject)A);

 77:   PetscLogStageRegister("mystage 2",&stage2);
 78:   PetscLogStagePush(stage2);
 79:   KSPSolve(ksp,b,x);
 80:   PetscLogStagePop();

 82:   /* Show result */
 83:   MatMult(A,x,u);
 84:   VecAXPY(u,-1.0,b);
 85:   VecNorm(u,NORM_2,&norm);
 86:   KSPGetIterationNumber(ksp,&its);
 87:   /*  matrix PC   KSP   Options       its    residual  */
 88:   if (table) {
 89:     char        *matrixname,kspinfo[120];
 90:     PetscViewer viewer;
 91:     PetscViewerStringOpen(PETSC_COMM_WORLD,kspinfo,sizeof(kspinfo),&viewer);
 92:     KSPView(ksp,viewer);
 93:     PetscStrrchr(file,'/',&matrixname);
 94:     PetscPrintf(PETSC_COMM_WORLD,"%-8.8s %3D %2.0e %s \n",matrixname,its,norm,kspinfo);
 95:     PetscViewerDestroy(&viewer);
 96:   } else {
 97:     PetscPrintf(PETSC_COMM_WORLD,"Number of iterations = %3D\n",its);
 98:     PetscPrintf(PETSC_COMM_WORLD,"Residual norm = %g\n",(double)norm);
 99:   }

101:   /* Cleanup */
102:   KSPDestroy(&ksp);
103:   VecDestroy(&x);
104:   VecDestroy(&b);
105:   VecDestroy(&u);
106:   MatDestroy(&A);
107:   PetscFinalize();
108:   return ierr;
109: }

111: /*TEST

113:     test:
114:       args: -ksp_type preonly  -pc_type lu -options_left no  -f ${DATAFILESPATH}/matrices/arco1 
115:       requires: datafilespath double !complex !define(PETSC_USE_64BIT_INDICES)

117:     test:
118:       suffix: 2
119:       args: -sub_pc_type ilu -options_left no  -f ${DATAFILESPATH}/matrices/arco1 -ksp_gmres_restart 100 -ksp_gmres_cgs_refinement_type refine_always -sub_ksp_type preonly -pc_type bjacobi -pc_bjacobi_blocks 8 -sub_pc_factor_in_place -ksp_monitor_short
120:       requires: datafilespath double  !complex !define(PETSC_USE_64BIT_INDICES)

122:     test:
123:       suffix: 7
124:       args: -ksp_gmres_cgs_refinement_type refine_always -pc_type asm -pc_asm_blocks 6 -f ${DATAFILESPATH}/matrices/small -matload_block_size 6  -ksp_monitor_short  
125:       requires: datafilespath double  !complex !define(PETSC_USE_64BIT_INDICES)

127: TEST*/