Date: 2026-01-20T11:35:22+00:00

Actual source code: test8.c

      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */

     11: static char help[] = "Test BV orthogonalization with selected columns.\n\n";

     13: #include <slepcbv.h>

     15: int main(int argc,char **argv)
     16: {
     17:   BV             X;
     18:   Vec            v,t,z;
     19:   PetscInt       i,j,n=20,k=8;
     20:   PetscViewer    view;
     21:   PetscBool      verbose,*which;
     22:   PetscReal      norm;
     23:   PetscScalar    alpha,*pz;

     25:   PetscFunctionBeginUser;
     26:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
     27:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     28:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL));
     29:   PetscCall(PetscOptionsHasName(NULL,NULL,"-verbose",&verbose));
     30:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Test BV orthogonalization with selected columns of length %" PetscInt_FMT ".\n",n));

     32:   /* Create template vector */
     33:   PetscCall(VecCreate(PETSC_COMM_WORLD,&t));
     34:   PetscCall(VecSetSizes(t,PETSC_DECIDE,n));
     35:   PetscCall(VecSetFromOptions(t));

     37:   /* Create BV object X */
     38:   PetscCall(BVCreate(PETSC_COMM_WORLD,&X));
     39:   PetscCall(PetscObjectSetName((PetscObject)X,"X"));
     40:   PetscCall(BVSetSizesFromVec(X,t,k));
     41:   PetscCall(BVSetOrthogonalization(X,BV_ORTHOG_MGS,BV_ORTHOG_REFINE_IFNEEDED,PETSC_CURRENT,BV_ORTHOG_BLOCK_GS));
     42:   PetscCall(BVSetFromOptions(X));

     44:   /* Set up viewer */
     45:   PetscCall(PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&view));
     46:   if (verbose) PetscCall(PetscViewerPushFormat(view,PETSC_VIEWER_ASCII_MATLAB));

     48:   /* Fill X entries */
     49:   for (j=0;j<k;j++) {
     50:     PetscCall(BVGetColumn(X,j,&v));
     51:     PetscCall(VecSet(v,0.0));
     52:     for (i=0;i<=n/2;i++) {
     53:       if (i+j<n) {
     54:         alpha = (3.0*i+j-2)/(2*(i+j+1));
     55:         PetscCall(VecSetValue(v,i+j,alpha,INSERT_VALUES));
     56:       }
     57:     }
     58:     PetscCall(VecAssemblyBegin(v));
     59:     PetscCall(VecAssemblyEnd(v));
     60:     PetscCall(BVRestoreColumn(X,j,&v));
     61:   }
     62:   if (verbose) PetscCall(BVView(X,view));

     64:   /* Orthonormalize first k-1 columns */
     65:   for (j=0;j<k-1;j++) {
     66:     PetscCall(BVOrthogonalizeColumn(X,j,NULL,&norm,NULL));
     67:     alpha = 1.0/norm;
     68:     PetscCall(BVScaleColumn(X,j,alpha));
     69:   }
     70:   if (verbose) PetscCall(BVView(X,view));

     72:   /* Select odd columns and orthogonalize last column against those only */
     73:   PetscCall(PetscMalloc1(k,&which));
     74:   for (i=0;i<k;i++) which[i] = (i%2)? PETSC_TRUE: PETSC_FALSE;
     75:   PetscCall(BVOrthogonalizeSomeColumn(X,k-1,which,NULL,NULL,NULL));
     76:   PetscCall(PetscFree(which));
     77:   if (verbose) PetscCall(BVView(X,view));

     79:   /* Check orthogonality */
     80:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Orthogonalization coefficients:\n"));
     81:   PetscCall(VecCreateSeq(PETSC_COMM_SELF,k-1,&z));
     82:   PetscCall(PetscObjectSetName((PetscObject)z,"z"));
     83:   PetscCall(VecGetArray(z,&pz));
     84:   PetscCall(BVDotColumn(X,k-1,pz));
     85:   for (i=0;i<k-1;i++) {
     86:     if (PetscAbsScalar(pz[i])<5.0*PETSC_MACHINE_EPSILON) pz[i]=0.0;
     87:   }
     88:   PetscCall(VecRestoreArray(z,&pz));
     89:   PetscCall(VecView(z,view));
     90:   PetscCall(VecDestroy(&z));

     92:   PetscCall(BVDestroy(&X));
     93:   PetscCall(VecDestroy(&t));
     94:   PetscCall(SlepcFinalize());
     95:   return 0;
     96: }

     98: /*TEST

    100:    testset:
    101:       output_file: output/test8_1.out
    102:       test:
    103:          suffix: 1
    104:          args: -bv_type {{vecs contiguous svec mat}shared output}
    105:       test:
    106:          suffix: 1_cuda
    107:          args: -bv_type {{svec mat}} -vec_type cuda
    108:          requires: cuda
    109:       test:
    110:          suffix: 1_hip
    111:          args: -bv_type {{svec mat}} -vec_type hip
    112:          requires: hip
    113:       test:
    114:          suffix: 2
    115:          args: -bv_type {{vecs contiguous svec mat}shared output} -bv_orthog_refine never
    116:          requires: !single
    117:       test:
    118:          suffix: 3
    119:          args: -bv_type {{vecs contiguous svec mat}shared output} -bv_orthog_refine always

    121: TEST*/