Actual source code: test15.c

slepc-3.7.1 2016-05-27
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain

  6:    This file is part of SLEPc.

  8:    SLEPc is free software: you can redistribute it and/or modify it under  the
  9:    terms of version 3 of the GNU Lesser General Public License as published by
 10:    the Free Software Foundation.

 12:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
 13:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
 14:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
 15:    more details.

 17:    You  should have received a copy of the GNU Lesser General  Public  License
 18:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
 19:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 20: */

 22: static char help[] = "Test DSPEP.\n\n";

 24: #include <slepcds.h>

 28: int main(int argc,char **argv)
 29: {
 31:   DS             ds;
 32:   SlepcSC        sc;
 33:   PetscScalar    *K,*C,*M,*wr,*wi,z=1.0;
 34:   PetscReal      re,im;
 35:   PetscInt       i,n=10,d=2,ld;
 36:   PetscViewer    viewer;
 37:   PetscBool      verbose;

 39:   SlepcInitialize(&argc,&argv,(char*)0,help);
 40:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 41:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type PEP - n=%D.\n",n);
 42:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

 44:   /* Create DS object */
 45:   DSCreate(PETSC_COMM_WORLD,&ds);
 46:   DSSetType(ds,DSPEP);
 47:   DSSetFromOptions(ds);
 48:   DSPEPSetDegree(ds,d);

 50:   /* Set dimensions */
 51:   ld = n+2;  /* test leading dimension larger than n */
 52:   DSAllocate(ds,ld);
 53:   DSSetDimensions(ds,n,0,0,0);

 55:   /* Set up viewer */
 56:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 57:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 58:   DSView(ds,viewer);
 59:   PetscViewerPopFormat(viewer);
 60:   if (verbose) {
 61:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
 62:   }

 64:   /* Fill matrices */
 65:   DSGetArray(ds,DS_MAT_E0,&K);
 66:   for (i=0;i<n-1;i++) K[i+i*ld] = 2.0*n;
 67:   K[n-1+(n-1)*ld] = 1.0*n;
 68:   for (i=1;i<n;i++) {
 69:     K[i+(i-1)*ld] = -1.0*n;
 70:     K[(i-1)+i*ld] = -1.0*n;
 71:   }
 72:   DSRestoreArray(ds,DS_MAT_E0,&K);
 73:   DSGetArray(ds,DS_MAT_E1,&C);
 74:   C[n-1+(n-1)*ld] = 2.0*PETSC_PI/z;
 75:   DSRestoreArray(ds,DS_MAT_E1,&C);
 76:   DSGetArray(ds,DS_MAT_E2,&M);
 77:   for (i=0;i<n-1;i++) M[i+i*ld] = -4.0*PETSC_PI*PETSC_PI/n;
 78:   M[i+i*ld] = -2.0*PETSC_PI*PETSC_PI/n;
 79:   DSRestoreArray(ds,DS_MAT_E2,&M);

 81:   if (verbose) {
 82:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 83:     DSView(ds,viewer);
 84:   }

 86:   /* Solve */
 87:   PetscMalloc2(d*n,&wr,d*n,&wi);
 88:   DSGetSlepcSC(ds,&sc);
 89:   sc->comparison    = SlepcCompareLargestReal;
 90:   sc->comparisonctx = NULL;
 91:   sc->map           = NULL;
 92:   sc->mapobj        = NULL;
 93:   DSSolve(ds,wr,wi);
 94:   DSSort(ds,wr,wi,NULL,NULL,NULL);
 95:   if (verbose) {
 96:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 97:     DSView(ds,viewer);
 98:   }

100:   /* Print first eigenvalue */
101:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
102:   for (i=0;i<d*n;i++) {
103: #if defined(PETSC_USE_COMPLEX)
104:     re = PetscRealPart(wr[i]);
105:     im = PetscImaginaryPart(wr[i]);
106: #else
107:     re = wr[i];
108:     im = wi[i];
109: #endif
110:     if (PetscAbs(im)<1e-10) {
111:       PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);
112:     } else {
113:       PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);
114:     }
115:   }

117:   PetscFree2(wr,wi);
118:   DSDestroy(&ds);
119:   SlepcFinalize();
120:   return ierr;
121: }