Actual source code: test4.c

slepc-3.11.2 2019-07-30
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2019, 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: {
 18:   DS             ds;
 19:   SlepcSC        sc;
 20:   PetscScalar    *A,*B,*X,*wr,*wi;
 21:   PetscReal      re,im,rnorm,aux;
 22:   PetscInt       i,j,n=10,ld;
 23:   PetscViewer    viewer;
 24:   PetscBool      verbose;

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

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

 39:   /* Set up viewer */
 40:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 41:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 42:   DSView(ds,viewer);
 43:   PetscViewerPopFormat(viewer);
 44:   if (verbose) {
 45:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
 46:   }

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

 64:   if (verbose) {
 65:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 66:     DSView(ds,viewer);
 67:   }

 69:   /* Solve */
 70:   PetscMalloc2(n,&wr,n,&wi);
 71:   DSGetSlepcSC(ds,&sc);
 72:   sc->comparison    = SlepcCompareLargestMagnitude;
 73:   sc->comparisonctx = NULL;
 74:   sc->map           = NULL;
 75:   sc->mapobj        = NULL;
 76:   DSSolve(ds,wr,wi);
 77:   DSSort(ds,wr,wi,NULL,NULL,NULL);
 78:   if (verbose) {
 79:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 80:     DSView(ds,viewer);
 81:   }

 83:   /* Print eigenvalues */
 84:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
 85:   for (i=0;i<n;i++) {
 86: #if defined(PETSC_USE_COMPLEX)
 87:     re = PetscRealPart(wr[i]);
 88:     im = PetscImaginaryPart(wr[i]);
 89: #else
 90:     re = wr[i];
 91:     im = wi[i];
 92: #endif
 93:     if (PetscAbs(im)<1e-10) {
 94:       PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);
 95:     } else {
 96:       PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);
 97:     }
 98:   }

100:   /* Eigenvectors */
101:   j = 1;
102:   DSVectors(ds,DS_MAT_X,&j,&rnorm);  /* second eigenvector */
103:   PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 2nd vector = %.3f\n",(double)rnorm);
104:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all eigenvectors */
105:   j = 0;
106:   rnorm = 0.0;
107:   DSGetArray(ds,DS_MAT_X,&X);
108:   for (i=0;i<n;i++) {
109: #if defined(PETSC_USE_COMPLEX)
110:     aux = PetscAbsScalar(X[i+j*ld]);
111: #else
112:     if (PetscAbs(wi[j])==0.0) aux = PetscAbsScalar(X[i+j*ld]);
113:     else aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
114: #endif
115:     rnorm += aux*aux;
116:   }
117:   DSRestoreArray(ds,DS_MAT_X,&X);
118:   rnorm = PetscSqrtReal(rnorm);
119:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm);
120:   if (verbose) {
121:     PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
122:     DSView(ds,viewer);
123:   }

125:   PetscFree2(wr,wi);
126:   DSDestroy(&ds);
127:   SlepcFinalize();
128:   return ierr;
129: }

131: /*TEST

133:    test:
134:       suffix: 1
135:       requires: !complex

137: TEST*/