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 DSPEP with complex eigenvalues.\n\n";

 13: #include <slepcds.h>

 15: int main(int argc,char **argv)
 16: {
 17:   DS             ds;
 18:   SlepcSC        sc;
 19:   Mat            X;
 20:   Vec            x0;
 21:   PetscScalar    *K,*M,*wr,*wi;
 22:   PetscReal      re,im,nrm;
 23:   PetscInt       i,n=10,d=2,ld;
 24:   PetscViewer    viewer;
 25:   PetscBool      verbose;

 27:   PetscFunctionBeginUser;
 28:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
 29:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
 30:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type PEP - n=%" PetscInt_FMT ".\n",n));
 31:   PetscCall(PetscOptionsHasName(NULL,NULL,"-verbose",&verbose));

 33:   /* Create DS object */
 34:   PetscCall(DSCreate(PETSC_COMM_WORLD,&ds));
 35:   PetscCall(DSSetType(ds,DSPEP));
 36:   PetscCall(DSSetFromOptions(ds));
 37:   PetscCall(DSPEPSetDegree(ds,d));

 39:   /* Set dimensions */
 40:   ld = n+2;  /* test leading dimension larger than n */
 41:   PetscCall(DSAllocate(ds,ld));
 42:   PetscCall(DSSetDimensions(ds,n,0,0));

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

 51:   /* Fill matrices */
 52:   PetscCall(DSGetArray(ds,DS_MAT_E0,&K));
 53:   for (i=0;i<n;i++) K[i+i*ld] = 2.0;
 54:   for (i=1;i<n;i++) {
 55:     K[i+(i-1)*ld] = -1.0;
 56:     K[(i-1)+i*ld] = -1.0;
 57:   }
 58:   PetscCall(DSRestoreArray(ds,DS_MAT_E0,&K));
 59:   PetscCall(DSGetArray(ds,DS_MAT_E2,&M));
 60:   for (i=0;i<n;i++) M[i+i*ld] = 1.0;
 61:   PetscCall(DSRestoreArray(ds,DS_MAT_E2,&M));

 63:   if (verbose) {
 64:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n"));
 65:     PetscCall(DSView(ds,viewer));
 66:   }

 68:   /* Solve */
 69:   PetscCall(PetscMalloc2(d*n,&wr,d*n,&wi));
 70:   PetscCall(DSGetSlepcSC(ds,&sc));
 71:   sc->comparison    = SlepcCompareLargestImaginary;
 72:   sc->comparisonctx = NULL;
 73:   sc->map           = NULL;
 74:   sc->mapobj        = NULL;
 75:   PetscCall(DSSolve(ds,wr,wi));
 76:   PetscCall(DSSort(ds,wr,wi,NULL,NULL,NULL));
 77:   if (verbose) {
 78:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n"));
 79:     PetscCall(DSView(ds,viewer));
 80:   }

 82:   /* Print eigenvalues */
 83:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n"));
 84:   for (i=0;i<d*n;i++) {
 85: #if defined(PETSC_USE_COMPLEX)
 86:     re = PetscRealPart(wr[i]);
 87:     im = PetscImaginaryPart(wr[i]);
 88: #else
 89:     re = wr[i];
 90:     im = wi[i];
 91: #endif
 92:     if (PetscAbs(im)<1e-10) PetscCall(PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re));
 93:     else PetscCall(PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im));
 94:   }

 96:   /* Eigenvectors */
 97:   PetscCall(DSVectors(ds,DS_MAT_X,NULL,NULL));  /* all eigenvectors */
 98:   PetscCall(DSGetMat(ds,DS_MAT_X,&X));
 99:   PetscCall(MatCreateVecs(X,NULL,&x0));
100:   PetscCall(MatGetColumnVector(X,x0,1));
101:   PetscCall(VecNorm(x0,NORM_2,&nrm));
102:   PetscCall(DSRestoreMat(ds,DS_MAT_X,&X));
103:   PetscCall(VecDestroy(&x0));
104:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Norm of 2nd column of X = %.3f\n",(double)nrm));
105:   if (verbose) {
106:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n"));
107:     PetscCall(DSView(ds,viewer));
108:   }

110:   PetscCall(PetscFree2(wr,wi));
111:   PetscCall(DSDestroy(&ds));
112:   PetscCall(SlepcFinalize());
113:   return 0;
114: }

116: /*TEST

118:    test:
119:       suffix: 1
120:       args: -n 7
121:       requires: !complex
122:       filter: sed -e 's/-0.00000/0.00000/'

124:    test:
125:       suffix: 1_complex
126:       args: -n 7
127:       requires: complex
128:       filter: sed -e 's/-0.00000/0.00000/'

130: TEST*/