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 created from a Mat.\n\n";

 13: #include <slepcbv.h>

 15: int main(int argc,char **argv)
 16: {
 17:   BV             X;
 18:   Mat            A,B,M;
 19:   PetscInt       i,j,n=20,k=8,Istart,Iend;
 20:   PetscViewer    view;
 21:   PetscBool      sparse=PETSC_FALSE,verbose;
 22:   PetscReal      norm;
 23:   PetscScalar    alpha;

 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,"-sparse",&sparse));
 30:   PetscCall(PetscOptionsHasName(NULL,NULL,"-verbose",&verbose));
 31:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Test BV created from a %s Mat (length %" PetscInt_FMT ", k=%" PetscInt_FMT ").\n",sparse?"sparse":"dense",n,k));

 33:   /* Create matrix */
 34:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
 35:   PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,k));
 36:   if (!sparse) PetscCall(MatSetType(A,MATDENSE));
 37:   else PetscCall(MatSetType(A,MATAIJ));
 38:   PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
 39:   for (j=0;j<k;j++) {
 40:     for (i=0;i<=n/2;i++) {
 41:       if (i+j<n && i>=Istart && i<Iend) {
 42:         alpha = (3.0*i+j-2)/(2*(i+j+1));
 43:         PetscCall(MatSetValue(A,i+j,j,alpha,INSERT_VALUES));
 44:       }
 45:     }
 46:   }
 47:   PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
 48:   PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));

 50:   /* Create BV object X */
 51:   PetscCall(BVCreateFromMat(A,&X));
 52:   PetscCall(BVSetFromOptions(X));
 53:   PetscCall(PetscObjectSetName((PetscObject)X,"X"));

 55:   /* Set up viewer */
 56:   PetscCall(PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&view));
 57:   if (verbose) {
 58:     PetscCall(PetscViewerPushFormat(view,PETSC_VIEWER_ASCII_MATLAB));
 59:     PetscCall(BVView(X,view));
 60:   }

 62:   /* Test BVCreateMat */
 63:   PetscCall(BVCreateMat(X,&B));
 64:   PetscCall(MatAXPY(B,-1.0,A,SAME_NONZERO_PATTERN));
 65:   PetscCall(MatNorm(B,NORM_1,&norm));
 66:   if (norm<100*PETSC_MACHINE_EPSILON) PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Norm of difference < 100*eps\n"));
 67:   else PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Norm of difference: %g\n",(double)norm));

 69:   /* Test BVOrthogonalize */
 70:   PetscCall(BVOrthogonalize(X,NULL));
 71:   if (verbose) PetscCall(BVView(X,view));

 73:   /* Check orthogonality */
 74:   PetscCall(MatCreateSeqDense(PETSC_COMM_SELF,k,k,NULL,&M));
 75:   PetscCall(MatShift(M,1.0));   /* set leading part to identity */
 76:   PetscCall(BVDot(X,X,M));
 77:   PetscCall(MatShift(M,-1.0));
 78:   PetscCall(MatNorm(M,NORM_1,&norm));
 79:   if (norm<100*PETSC_MACHINE_EPSILON) PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality < 100*eps\n"));
 80:   else PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality: %g\n",(double)norm));

 82:   PetscCall(MatDestroy(&M));
 83:   PetscCall(MatDestroy(&A));
 84:   PetscCall(MatDestroy(&B));
 85:   PetscCall(BVDestroy(&X));
 86:   PetscCall(SlepcFinalize());
 87:   return 0;
 88: }

 90: /*TEST

 92:    test:
 93:       suffix: 1
 94:       nsize: 2
 95:       args: -bv_type {{vecs contiguous svec mat}shared output}

 97:    test:
 98:       suffix: 2
 99:       args: -sparse

101: TEST*/