Actual source code: test21.c

slepc-3.17.1 2022-04-11
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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[] = "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:   PetscComplex   *eigs,eval;
 32:   PetscInt       N,m=15,nev,i,nconv;
 33:   PetscBool      checkfile;
 34:   char           filename[PETSC_MAX_PATH_LEN];
 35:   PetscViewer    viewer;
 36:   char           str[50];

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

 47:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 48:      Compute the operator matrix that defines the eigensystem, Ax=kx
 49:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

 57:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 58:                 Create a standalone spectral transformation
 59:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

 65:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 66:                     Create a region for filtering
 67:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

 74:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 75:                 Create the eigensolver and set various options
 76:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

 87:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 88:                Solve the eigensystem and display solution
 89:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

 96:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 97:                    Check file containing the eigenvalues
 98:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 99:   PetscOptionsGetString(NULL,NULL,"-checkfile",filename,sizeof(filename),&checkfile);
100:   if (checkfile) {
101:     EPSGetConverged(eps,&nconv);
102:     PetscMalloc1(nconv,&eigs);
103:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
104:     PetscViewerBinaryRead(viewer,eigs,nconv,NULL,PETSC_COMPLEX);
105:     PetscViewerDestroy(&viewer);
106:     for (i=0;i<nconv;i++) {
107:       EPSGetEigenpair(eps,i,&kr,&ki,NULL,NULL);
108: #if defined(PETSC_USE_COMPLEX)
109:       eval = kr;
110: #else
111:       eval = PetscCMPLX(kr,ki);
112: #endif
114:     }
115:     PetscFree(eigs);
116:   }

118:   EPSDestroy(&eps);
119:   STDestroy(&st);
120:   RGDestroy(&rg);
121:   MatDestroy(&A);
122: #else
123:   SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"This example requires C99 complex numbers");
124: #endif
125:   SlepcFinalize();
126:   return 0;
127: }

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

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

163: /*TEST

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

171: TEST*/