Actual source code: test13.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 DSHEP with block size larger than one.\n\n";

 24: #include <slepcds.h>

 28: int main(int argc,char **argv)
 29: {
 31:   DS             ds;
 32:   SlepcSC        sc;
 33:   PetscScalar    *A,*eig;
 34:   PetscInt       i,j,n,ld,bs,maxbw=3,nblks=8;
 35:   PetscViewer    viewer;
 36:   PetscBool      verbose;

 38:   SlepcInitialize(&argc,&argv,(char*)0,help);
 39:   PetscOptionsGetInt(NULL,NULL,"-maxbw",&maxbw,NULL);
 40:   PetscOptionsGetInt(NULL,NULL,"-nblks",&nblks,NULL);
 41:   n = maxbw*nblks;
 42:   bs = maxbw;
 43:   PetscPrintf(PETSC_COMM_WORLD,"Solve a block HEP Dense System - dimension %D (bandwidth=%D, blocks=%D).\n",n,maxbw,nblks);
 44:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

 46:   /* Create DS object */
 47:   DSCreate(PETSC_COMM_WORLD,&ds);
 48:   DSSetType(ds,DSHEP);
 49:   DSSetMethod(ds,3);   /* Select block divide-and-conquer */
 50:   DSSetBlockSize(ds,bs);
 51:   DSSetFromOptions(ds);
 52:   ld = n;
 53:   DSAllocate(ds,ld);
 54:   DSSetDimensions(ds,n,0,0,0);

 56:   /* Set up viewer */
 57:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 58:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 59:   DSView(ds,viewer);
 60:   PetscViewerPopFormat(viewer);
 61:   if (verbose) {
 62:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
 63:   }

 65:   /* Fill with a symmetric band Toeplitz matrix */
 66:   DSGetArray(ds,DS_MAT_A,&A);
 67:   for (i=0;i<n;i++) A[i+i*ld]=2.0;
 68:   for (j=1;j<=bs;j++) {
 69:     for (i=0;i<n-j;i++) { A[i+(i+j)*ld]=1.0; A[(i+j)+i*ld]=1.0; }
 70:   }
 71:   DSRestoreArray(ds,DS_MAT_A,&A);
 72:   DSSetState(ds,DS_STATE_RAW);
 73:   if (verbose) {
 74:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 75:     DSView(ds,viewer);
 76:   }

 78:   /* Solve */
 79:   PetscMalloc1(n,&eig);
 80:   DSGetSlepcSC(ds,&sc);
 81:   sc->comparison    = SlepcCompareSmallestReal;
 82:   sc->comparisonctx = NULL;
 83:   sc->map           = NULL;
 84:   sc->mapobj        = NULL;
 85:   DSSolve(ds,eig,NULL);
 86:   DSSort(ds,eig,NULL,NULL,NULL,NULL);
 87:   if (verbose) {
 88:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 89:     DSView(ds,viewer);
 90:   }

 92:   /* Print eigenvalues */
 93:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
 94:   for (i=0;i<n;i++) {
 95:     PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)PetscRealPart(eig[i]));
 96:   }

 98:   PetscFree(eig);
 99:   DSDestroy(&ds);
100:   SlepcFinalize();
101:   return ierr;
102: }