Actual source code: test19.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 DSSortWithPermutation() on a NHEP.\n\n";

 13: #include <slepcds.h>

 15: int main(int argc,char **argv)
 16: {
 17:   DS             ds;
 18:   SlepcSC        sc;
 19:   PetscScalar    *A,*wr,*wi;
 20:   PetscReal      re,im;
 21:   PetscInt       i,j,n=12,*perm;

 23:   SlepcInitialize(&argc,&argv,(char*)0,help);
 24:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 25:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type NHEP - dimension %" PetscInt_FMT ".\n",n);

 27:   /* Create DS object */
 28:   DSCreate(PETSC_COMM_WORLD,&ds);
 29:   DSSetType(ds,DSNHEP);
 30:   DSSetFromOptions(ds);
 31:   DSAllocate(ds,n);
 32:   DSSetDimensions(ds,n,0,0);

 34:   /* Fill with Grcar matrix */
 35:   DSGetArray(ds,DS_MAT_A,&A);
 36:   for (i=1;i<n;i++) A[i+(i-1)*n]=-1.0;
 37:   for (j=0;j<4;j++) {
 38:     for (i=0;i<n-j;i++) A[i+(i+j)*n]=1.0;
 39:   }
 40:   DSRestoreArray(ds,DS_MAT_A,&A);
 41:   DSSetState(ds,DS_STATE_INTERMEDIATE);

 43:   /* Solve */
 44:   PetscMalloc3(n,&wr,n,&wi,n,&perm);
 45:   DSGetSlepcSC(ds,&sc);
 46:   sc->comparison    = SlepcCompareLargestMagnitude;
 47:   sc->comparisonctx = NULL;
 48:   sc->map           = NULL;
 49:   sc->mapobj        = NULL;
 50:   DSSolve(ds,wr,wi);
 51:   DSSort(ds,wr,wi,NULL,NULL,NULL);

 53:   /* Print eigenvalues */
 54:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
 55:   for (i=0;i<n;i++) {
 56: #if defined(PETSC_USE_COMPLEX)
 57:     re = PetscRealPart(wr[i]);
 58:     im = PetscImaginaryPart(wr[i]);
 59: #else
 60:     re = wr[i];
 61:     im = wi[i];
 62: #endif
 63:     if (PetscAbs(im)<1e-10) PetscPrintf(PETSC_COMM_WORLD,"  %.5f\n",(double)re);
 64:     else PetscPrintf(PETSC_COMM_WORLD,"  %.5f%+.5fi\n",(double)re,(double)im);
 65:   }

 67:   /* Reorder eigenvalues */
 68:   for (i=0;i<n/2;i++) perm[i] = n/2+i;
 69:   for (i=0;i<n/2;i++) perm[i+n/2] = i;
 70:   DSSortWithPermutation(ds,perm,wr,wi);
 71:   PetscPrintf(PETSC_COMM_WORLD,"Reordered eigenvalues =\n");
 72:   for (i=0;i<n;i++) {
 73: #if defined(PETSC_USE_COMPLEX)
 74:     re = PetscRealPart(wr[i]);
 75:     im = PetscImaginaryPart(wr[i]);
 76: #else
 77:     re = wr[i];
 78:     im = wi[i];
 79: #endif
 80:     if (PetscAbs(im)<1e-10) PetscPrintf(PETSC_COMM_WORLD,"  %.5f\n",(double)re);
 81:     else PetscPrintf(PETSC_COMM_WORLD,"  %.5f%+.5fi\n",(double)re,(double)im);
 82:   }

 84:   PetscFree3(wr,wi,perm);
 85:   DSDestroy(&ds);
 86:   SlepcFinalize();
 87:   return 0;
 88: }

 90: /*TEST

 92:    test:
 93:       suffix: 1
 94:       filter: sed -e "s/[+-]\([0-9]\.[0-9]*i\)/+-\\1/" | sed -e "s/2.16612/2.16613/"

 96: TEST*/