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 DSHEP with compact storage.\n\n";

 13: #include <slepcds.h>

 15: int main(int argc,char **argv)
 16: {
 17:   DS             ds;
 18:   SlepcSC        sc;
 19:   PetscReal      *T;
 20:   PetscScalar    *Q,*eig,d;
 21:   PetscInt       i,n=10,l=2,k=5,ld;
 22:   PetscViewer    viewer;
 23:   PetscBool      verbose,extrarow;

 25:   PetscFunctionBeginUser;
 26:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
 27:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
 28:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type HEP with compact storage - dimension %" PetscInt_FMT ".\n",n));
 29:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-l",&l,NULL));
 30:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL));
 31:   PetscCheck(l<=n && k<=n && l<=k,PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"Wrong value of dimensions");
 32:   PetscCall(PetscOptionsHasName(NULL,NULL,"-verbose",&verbose));
 33:   PetscCall(PetscOptionsHasName(NULL,NULL,"-extrarow",&extrarow));

 35:   /* Create DS object */
 36:   PetscCall(DSCreate(PETSC_COMM_WORLD,&ds));
 37:   PetscCall(DSSetType(ds,DSHEP));
 38:   PetscCall(DSSetFromOptions(ds));
 39:   ld = n+2;  /* test leading dimension larger than n */
 40:   PetscCall(DSAllocate(ds,ld));
 41:   PetscCall(DSSetDimensions(ds,n,l,k));
 42:   PetscCall(DSSetCompact(ds,PETSC_TRUE));
 43:   PetscCall(DSSetExtraRow(ds,extrarow));

 45:   /* Set up viewer */
 46:   PetscCall(PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer));
 47:   PetscCall(PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL));
 48:   PetscCall(DSView(ds,viewer));
 49:   PetscCall(PetscViewerPopFormat(viewer));
 50:   PetscCall(PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB));

 52:   /* Fill arrow-tridiagonal matrix */
 53:   PetscCall(DSGetArrayReal(ds,DS_MAT_T,&T));
 54:   for (i=0;i<n;i++) T[i] = (PetscReal)(i+1);
 55:   for (i=l;i<n-1;i++) T[i+ld] = 1.0;
 56:   if (extrarow) T[n-1+ld] = 1.0;
 57:   PetscCall(DSRestoreArrayReal(ds,DS_MAT_T,&T));
 58:   if (l==0 && k==0) PetscCall(DSSetState(ds,DS_STATE_INTERMEDIATE));
 59:   else PetscCall(DSSetState(ds,DS_STATE_RAW));
 60:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n"));
 61:   PetscCall(DSView(ds,viewer));

 63:   /* Solve */
 64:   PetscCall(PetscMalloc1(n,&eig));
 65:   PetscCall(DSGetSlepcSC(ds,&sc));
 66:   sc->comparison    = SlepcCompareLargestMagnitude;
 67:   sc->comparisonctx = NULL;
 68:   sc->map           = NULL;
 69:   sc->mapobj        = NULL;
 70:   PetscCall(DSSolve(ds,eig,NULL));
 71:   PetscCall(DSSort(ds,eig,NULL,NULL,NULL,NULL));
 72:   if (extrarow) PetscCall(DSUpdateExtraRow(ds));
 73:   if (verbose) {
 74:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n"));
 75:     PetscCall(DSView(ds,viewer));
 76:   }

 78:   /* Print eigenvalues */
 79:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n"));
 80:   for (i=0;i<n;i++) PetscCall(PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)PetscRealPart(eig[i])));

 82:   if (extrarow) {
 83:     /* Check that extra row is correct */
 84:     PetscCall(DSGetArrayReal(ds,DS_MAT_T,&T));
 85:     PetscCall(DSGetArray(ds,DS_MAT_Q,&Q));
 86:     d = 0.0;
 87:     for (i=l;i<n;i++) d += T[i+ld]-Q[n-1+i*ld];
 88:     if (PetscAbsScalar(d)>10*PETSC_MACHINE_EPSILON) PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Warning: there is a mismatch in the extra row of %g\n",(double)PetscAbsScalar(d)));
 89:     PetscCall(DSRestoreArrayReal(ds,DS_MAT_T,&T));
 90:     PetscCall(DSRestoreArray(ds,DS_MAT_Q,&Q));
 91:   }
 92:   PetscCall(PetscFree(eig));
 93:   PetscCall(DSDestroy(&ds));
 94:   PetscCall(SlepcFinalize());
 95:   return 0;
 96: }

 98: /*TEST

100:    testset:
101:       args: -n 9 -ds_method {{0 1 2}}
102:       filter: grep -v "solving the problem" | sed -e "s/extrarow//"
103:       requires: !single
104:       test:
105:          suffix: 1
106:       test:
107:          suffix: 2
108:          args: -extrarow

110: TEST*/