Actual source code: test6.c

  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2012, Universitat Politecnica de Valencia, Spain

  6:    This file is part of SLEPc.
  7:       
  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 DSGHIEP with compact storage.\n\n";

 24:  #include slepcds.h

 28: int main( int argc, char **argv )
 29: {
 31:   DS             ds;
 32:   PetscReal      *T,*s,re,im;
 33:   PetscScalar    *eigr,*eigi;
 34:   PetscInt       i,n=10,l=2,k=5,ld;
 35:   PetscViewer    viewer;
 36:   PetscBool      verbose;

 38:   SlepcInitialize(&argc,&argv,(char*)0,help);
 39:   PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);
 40:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GHIEP with compact storage - dimension %D.\n",n);
 41:   PetscOptionsGetInt(PETSC_NULL,"-l",&l,PETSC_NULL);
 42:   PetscOptionsGetInt(PETSC_NULL,"-k",&k,PETSC_NULL);
 43:   if (l>n || k>n || l>k) SETERRQ(PETSC_COMM_WORLD,1,"Wrong value of dimensions");
 44:   PetscOptionsHasName(PETSC_NULL,"-verbose",&verbose);

 46:   /* Create DS object */
 47:   DSCreate(PETSC_COMM_WORLD,&ds);
 48:   DSSetType(ds,DSGHIEP);
 49:   DSSetFromOptions(ds);
 50:   ld = n+2;  /* test leading dimension larger than n */
 51:   DSAllocate(ds,ld);
 52:   DSSetDimensions(ds,n,PETSC_IGNORE,l,k);
 53:   DSSetCompact(ds,PETSC_TRUE);

 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 arrow-tridiagonal matrix */
 65:   DSGetArrayReal(ds,DS_MAT_T,&T);
 66:   DSGetArrayReal(ds,DS_MAT_D,&s);
 67:   for (i=0;i<n;i++) T[i] = (PetscReal)(i+1);
 68:   for (i=k;i<n-1;i++) T[i+ld] = 1.0;
 69:   for (i=l;i<k;i++) T[i+2*ld] = 1.0;
 70:   T[2*ld+l+1] = -7; T[ld+k+1] = -7;
 71:   /* Signature matrix */
 72:   for (i=0;i<n;i++) s[i] = 1.0;
 73:   s[l+1] = -1.0;
 74:   s[k+1] = -1.0;
 75:   DSRestoreArrayReal(ds,DS_MAT_T,&T);
 76:   DSRestoreArrayReal(ds,DS_MAT_D,&s);
 77:   if (l==0 && k==0) {
 78:     DSSetState(ds,DS_STATE_INTERMEDIATE);
 79:   } else {
 80:     DSSetState(ds,DS_STATE_RAW);
 81:   }
 82:   if (verbose) {
 83:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 84:     DSView(ds,viewer);
 85:   }

 87:   /* Solve */
 88:   PetscMalloc(n*sizeof(PetscScalar),&eigr);
 89:   PetscMalloc(n*sizeof(PetscScalar),&eigi);
 90:   PetscMemzero(eigi,n*sizeof(PetscScalar));
 91:   DSSetEigenvalueComparison(ds,SlepcCompareLargestMagnitude,PETSC_NULL);
 92:   DSSolve(ds,eigr,eigi);
 93:   DSSort(ds,eigr,eigi,PETSC_NULL,PETSC_NULL,PETSC_NULL);
 94:   if (verbose) {
 95:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 96:     DSView(ds,viewer);
 97:   }
 98: 
 99:   /* Print eigenvalues */
100:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n",n);
101:   for (i=0;i<n;i++) {
102: #if defined(PETSC_USE_COMPLEX)
103:     re = PetscRealPart(eigr[i]);
104:     im = PetscImaginaryPart(eigr[i]);
105: #else
106:     re = eigr[i];
107:     im = eigi[i];
108: #endif 
109:     if (PetscAbs(im)<1e-10) { PetscViewerASCIIPrintf(viewer,"  %.5F\n",re); }
110:     else { PetscViewerASCIIPrintf(viewer,"  %.5F%+.5Fi\n",re,im); }
111:   }
112:   PetscFree(eigr);
113:   PetscFree(eigi);
114:   DSDestroy(&ds);
115:   SlepcFinalize();
116:   return 0;
117: }