Actual source code: test4.c

slepc-3.17.2 2022-08-09
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  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 DSGNHEP.\n\n";

 13: #include <slepcds.h>

 15: int main(int argc,char **argv)
 16: {
 17:   DS             ds;
 18:   SlepcSC        sc;
 19:   PetscScalar    *A,*B,*X,*wr,*wi;
 20:   PetscReal      re,im,rnorm,aux;
 21:   PetscInt       i,j,n=10,ld;
 22:   PetscViewer    viewer;
 23:   PetscBool      verbose;

 25:   SlepcInitialize(&argc,&argv,(char*)0,help);
 26:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 27:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GNHEP - dimension %" PetscInt_FMT ".\n",n);
 28:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

 30:   /* Create DS object */
 31:   DSCreate(PETSC_COMM_WORLD,&ds);
 32:   DSSetType(ds,DSGNHEP);
 33:   DSSetFromOptions(ds);
 34:   ld = n+2;  /* test leading dimension larger than n */
 35:   DSAllocate(ds,ld);
 36:   DSSetDimensions(ds,n,0,0);

 38:   /* Set up viewer */
 39:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 40:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 41:   DSView(ds,viewer);
 42:   PetscViewerPopFormat(viewer);
 43:   if (verbose) PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);

 45:   /* Fill A with Grcar matrix */
 46:   DSGetArray(ds,DS_MAT_A,&A);
 47:   PetscArrayzero(A,ld*n);
 48:   for (i=1;i<n;i++) A[i+(i-1)*ld]=-1.0;
 49:   for (j=0;j<4;j++) {
 50:     for (i=0;i<n-j;i++) A[i+(i+j)*ld]=1.0;
 51:   }
 52:   DSRestoreArray(ds,DS_MAT_A,&A);
 53:   /* Fill B with an upper triangular matrix */
 54:   DSGetArray(ds,DS_MAT_B,&B);
 55:   PetscArrayzero(B,ld*n);
 56:   B[0+0*ld]=-1.0;
 57:   B[0+1*ld]=2.0;
 58:   for (i=1;i<n;i++) B[i+i*ld]=1.0;
 59:   DSRestoreArray(ds,DS_MAT_B,&B);

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

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

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

 94:   /* Eigenvectors */
 95:   j = 1;
 96:   DSVectors(ds,DS_MAT_X,&j,&rnorm);  /* second eigenvector */
 97:   PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 2nd vector = %.3f\n",(double)rnorm);
 98:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all eigenvectors */
 99:   j = 0;
100:   rnorm = 0.0;
101:   DSGetArray(ds,DS_MAT_X,&X);
102:   for (i=0;i<n;i++) {
103: #if defined(PETSC_USE_COMPLEX)
104:     aux = PetscAbsScalar(X[i+j*ld]);
105: #else
106:     if (PetscAbs(wi[j])==0.0) aux = PetscAbsScalar(X[i+j*ld]);
107:     else aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
108: #endif
109:     rnorm += aux*aux;
110:   }
111:   DSRestoreArray(ds,DS_MAT_X,&X);
112:   rnorm = PetscSqrtReal(rnorm);
113:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm);
114:   if (verbose) {
115:     PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
116:     DSView(ds,viewer);
117:   }

119:   PetscFree2(wr,wi);
120:   DSDestroy(&ds);
121:   SlepcFinalize();
122:   return 0;
123: }

125: /*TEST

127:    test:
128:       suffix: 1
129:       filter: sed -e "s/[+-]\([0-9]\.[0-9]*i\)/+-\\1/" | sed -e "s/+-0\.0*i//"

131: TEST*/