Actual source code: test21.c

slepc-3.18.2 2023-01-26
Report Typos and Errors
  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[] = "Illustrates region filtering. "
 12:   "Based on ex5.\n"
 13:   "The command line options are:\n"
 14:   "  -m <m>, where <m> = number of grid subdivisions in each dimension.\n\n";

 16: #include <slepceps.h>

 18: /*
 19:    User-defined routines
 20: */
 21: PetscErrorCode MatMarkovModel(PetscInt m,Mat A);

 23: int main(int argc,char **argv)
 24: {
 25:   Mat            A;
 26:   EPS            eps;
 27:   ST             st;
 28:   RG             rg;
 29:   PetscReal      radius,tol=PETSC_SMALL;
 30:   PetscScalar    target=0.5,kr,ki;
 31:   PetscInt       N,m=15,nev,i,nconv;
 32:   PetscBool      checkfile;
 33:   char           filename[PETSC_MAX_PATH_LEN];
 34:   PetscViewer    viewer;
 35:   char           str[50];

 38:   SlepcInitialize(&argc,&argv,(char*)0,help);
 39:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
 40:   N = m*(m+1)/2;
 41:   PetscPrintf(PETSC_COMM_WORLD,"\nMarkov Model, N=%" PetscInt_FMT " (m=%" PetscInt_FMT ")\n",N,m);
 42:   PetscOptionsGetScalar(NULL,NULL,"-target",&target,NULL);
 43:   SlepcSNPrintfScalar(str,sizeof(str),target,PETSC_FALSE);
 44:   PetscPrintf(PETSC_COMM_WORLD,"Searching closest eigenvalues to the right of %s.\n\n",str);

 46:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 47:      Compute the operator matrix that defines the eigensystem, Ax=kx
 48:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 50:   MatCreate(PETSC_COMM_WORLD,&A);
 51:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
 52:   MatSetFromOptions(A);
 53:   MatSetUp(A);
 54:   MatMarkovModel(m,A);

 56:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 57:                 Create a standalone spectral transformation
 58:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 60:   STCreate(PETSC_COMM_WORLD,&st);
 61:   STSetType(st,STSINVERT);
 62:   STSetShift(st,target);

 64:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 65:                     Create a region for filtering
 66:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 68:   RGCreate(PETSC_COMM_WORLD,&rg);
 69:   RGSetType(rg,RGELLIPSE);
 70:   radius = (1.0-PetscRealPart(target))/2.0;
 71:   RGEllipseSetParameters(rg,target+radius,radius,0.1);

 73:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 74:                 Create the eigensolver and set various options
 75:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 77:   EPSCreate(PETSC_COMM_WORLD,&eps);
 78:   EPSSetST(eps,st);
 79:   EPSSetRG(eps,rg);
 80:   EPSSetOperators(eps,A,NULL);
 81:   EPSSetProblemType(eps,EPS_NHEP);
 82:   EPSSetTolerances(eps,tol,PETSC_DEFAULT);
 83:   EPSSetTarget(eps,target);
 84:   EPSSetFromOptions(eps);

 86:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 87:                Solve the eigensystem and display solution
 88:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 90:   EPSSolve(eps);
 91:   EPSGetDimensions(eps,&nev,NULL,NULL);
 92:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev);
 93:   EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);

 95:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 96:                    Check file containing the eigenvalues
 97:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 98:   PetscOptionsGetString(NULL,NULL,"-checkfile",filename,sizeof(filename),&checkfile);
 99:   if (checkfile) {
100: #if defined(PETSC_HAVE_COMPLEX)
101:   PetscComplex *eigs,eval;
102:     EPSGetConverged(eps,&nconv);
103:     PetscMalloc1(nconv,&eigs);
104:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
105:     PetscViewerBinaryRead(viewer,eigs,nconv,NULL,PETSC_COMPLEX);
106:     PetscViewerDestroy(&viewer);
107:     for (i=0;i<nconv;i++) {
108:       EPSGetEigenpair(eps,i,&kr,&ki,NULL,NULL);
109: #if defined(PETSC_USE_COMPLEX)
110:       eval = kr;
111: #else
112:       eval = PetscCMPLX(kr,ki);
113: #endif
115:     }
116:     PetscFree(eigs);
117: #else
118:     SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"The -checkfile option requires C99 complex numbers");
119: #endif
120:   }

122:   EPSDestroy(&eps);
123:   STDestroy(&st);
124:   RGDestroy(&rg);
125:   MatDestroy(&A);
126:   SlepcFinalize();
127:   return 0;
128: }

130: PetscErrorCode MatMarkovModel(PetscInt m,Mat A)
131: {
132:   const PetscReal cst = 0.5/(PetscReal)(m-1);
133:   PetscReal       pd,pu;
134:   PetscInt        Istart,Iend,i,j,jmax,ix=0;

137:   MatGetOwnershipRange(A,&Istart,&Iend);
138:   for (i=1;i<=m;i++) {
139:     jmax = m-i+1;
140:     for (j=1;j<=jmax;j++) {
141:       ix = ix + 1;
142:       if (ix-1<Istart || ix>Iend) continue;  /* compute only owned rows */
143:       if (j!=jmax) {
144:         pd = cst*(PetscReal)(i+j-1);
145:         /* north */
146:         if (i==1) MatSetValue(A,ix-1,ix,2*pd,INSERT_VALUES);
147:         else MatSetValue(A,ix-1,ix,pd,INSERT_VALUES);
148:         /* east */
149:         if (j==1) MatSetValue(A,ix-1,ix+jmax-1,2*pd,INSERT_VALUES);
150:         else MatSetValue(A,ix-1,ix+jmax-1,pd,INSERT_VALUES);
151:       }
152:       /* south */
153:       pu = 0.5 - cst*(PetscReal)(i+j-3);
154:       if (j>1) MatSetValue(A,ix-1,ix-2,pu,INSERT_VALUES);
155:       /* west */
156:       if (i>1) MatSetValue(A,ix-1,ix-jmax-2,pu,INSERT_VALUES);
157:     }
158:   }
159:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
160:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
161:   return 0;
162: }

164: /*TEST

166:    test:
167:       suffix: 1
168:       args: -eps_nev 4 -eps_ncv 20 -eps_view_values binary:myvalues.bin -checkfile myvalues.bin
169:       output_file: output/test11_1.out
170:       requires: !single c99_complex

172: TEST*/