Actual source code: test9.c

slepc-3.18.2 2023-01-26
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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 use of PEPSetEigenvalueComparison().\n\n"
 12:   "Based on butterfly.c. The command line options are:\n"
 13:   "  -m <m>, grid size, the dimension of the matrices is n=m*m.\n"
 14:   "  -c <array>, problem parameters, must be 10 comma-separated real values.\n\n";

 16: #include <slepcpep.h>

 18: #define NMAT 5

 20: /*
 21:     Function for user-defined eigenvalue ordering criterion.

 23:     Given two eigenvalues ar+i*ai and br+i*bi, the subroutine must choose
 24:     one of them as the preferred one according to the criterion.
 25:     In this example, eigenvalues are sorted by magnitude but those with
 26:     positive real part are preferred.
 27: */
 28: PetscErrorCode MyEigenSort(PetscScalar ar,PetscScalar ai,PetscScalar br,PetscScalar bi,PetscInt *r,void *ctx)
 29: {
 30:   PetscReal rea,reb;

 33: #if defined(PETSC_USE_COMPLEX)
 34:   rea = PetscRealPart(ar); reb = PetscRealPart(br);
 35: #else
 36:   rea = ar; reb = br;
 37: #endif
 38:   *r = rea<0.0? 1: (reb<0.0? -1: PetscSign(SlepcAbsEigenvalue(br,bi)-SlepcAbsEigenvalue(ar,ai)));
 39:   return 0;
 40: }

 42: int main(int argc,char **argv)
 43: {
 44:   Mat            A[NMAT];         /* problem matrices */
 45:   PEP            pep;             /* polynomial eigenproblem solver context */
 46:   PetscInt       n,m=8,k,II,Istart,Iend,i,j;
 47:   PetscReal      c[10] = { 0.6, 1.3, 1.3, 0.1, 0.1, 1.2, 1.0, 1.0, 1.2, 1.0 };
 48:   PetscBool      flg;
 49:   PetscBool      terse;
 50:   const char     *prefix;

 53:   SlepcInitialize(&argc,&argv,(char*)0,help);

 55:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
 56:   n = m*m;
 57:   k = 10;
 58:   PetscOptionsGetRealArray(NULL,NULL,"-c",c,&k,&flg);
 60:   PetscPrintf(PETSC_COMM_WORLD,"\nButterfly problem, n=%" PetscInt_FMT " (m=%" PetscInt_FMT ")\n\n",n,m);

 62:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 63:                      Compute the polynomial matrices
 64:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 66:   /* initialize matrices */
 67:   for (i=0;i<NMAT;i++) {
 68:     MatCreate(PETSC_COMM_WORLD,&A[i]);
 69:     MatSetSizes(A[i],PETSC_DECIDE,PETSC_DECIDE,n,n);
 70:     MatSetFromOptions(A[i]);
 71:     MatSetUp(A[i]);
 72:   }
 73:   MatGetOwnershipRange(A[0],&Istart,&Iend);

 75:   /* A0 */
 76:   for (II=Istart;II<Iend;II++) {
 77:     i = II/m; j = II-i*m;
 78:     MatSetValue(A[0],II,II,4.0*c[0]/6.0+4.0*c[1]/6.0,INSERT_VALUES);
 79:     if (j>0) MatSetValue(A[0],II,II-1,c[0]/6.0,INSERT_VALUES);
 80:     if (j<m-1) MatSetValue(A[0],II,II+1,c[0]/6.0,INSERT_VALUES);
 81:     if (i>0) MatSetValue(A[0],II,II-m,c[1]/6.0,INSERT_VALUES);
 82:     if (i<m-1) MatSetValue(A[0],II,II+m,c[1]/6.0,INSERT_VALUES);
 83:   }

 85:   /* A1 */
 86:   for (II=Istart;II<Iend;II++) {
 87:     i = II/m; j = II-i*m;
 88:     if (j>0) MatSetValue(A[1],II,II-1,c[2],INSERT_VALUES);
 89:     if (j<m-1) MatSetValue(A[1],II,II+1,-c[2],INSERT_VALUES);
 90:     if (i>0) MatSetValue(A[1],II,II-m,c[3],INSERT_VALUES);
 91:     if (i<m-1) MatSetValue(A[1],II,II+m,-c[3],INSERT_VALUES);
 92:   }

 94:   /* A2 */
 95:   for (II=Istart;II<Iend;II++) {
 96:     i = II/m; j = II-i*m;
 97:     MatSetValue(A[2],II,II,-2.0*c[4]-2.0*c[5],INSERT_VALUES);
 98:     if (j>0) MatSetValue(A[2],II,II-1,c[4],INSERT_VALUES);
 99:     if (j<m-1) MatSetValue(A[2],II,II+1,c[4],INSERT_VALUES);
100:     if (i>0) MatSetValue(A[2],II,II-m,c[5],INSERT_VALUES);
101:     if (i<m-1) MatSetValue(A[2],II,II+m,c[5],INSERT_VALUES);
102:   }

104:   /* A3 */
105:   for (II=Istart;II<Iend;II++) {
106:     i = II/m; j = II-i*m;
107:     if (j>0) MatSetValue(A[3],II,II-1,c[6],INSERT_VALUES);
108:     if (j<m-1) MatSetValue(A[3],II,II+1,-c[6],INSERT_VALUES);
109:     if (i>0) MatSetValue(A[3],II,II-m,c[7],INSERT_VALUES);
110:     if (i<m-1) MatSetValue(A[3],II,II+m,-c[7],INSERT_VALUES);
111:   }

113:   /* A4 */
114:   for (II=Istart;II<Iend;II++) {
115:     i = II/m; j = II-i*m;
116:     MatSetValue(A[4],II,II,2.0*c[8]+2.0*c[9],INSERT_VALUES);
117:     if (j>0) MatSetValue(A[4],II,II-1,-c[8],INSERT_VALUES);
118:     if (j<m-1) MatSetValue(A[4],II,II+1,-c[8],INSERT_VALUES);
119:     if (i>0) MatSetValue(A[4],II,II-m,-c[9],INSERT_VALUES);
120:     if (i<m-1) MatSetValue(A[4],II,II+m,-c[9],INSERT_VALUES);
121:   }

123:   /* assemble matrices */
124:   for (i=0;i<NMAT;i++) MatAssemblyBegin(A[i],MAT_FINAL_ASSEMBLY);
125:   for (i=0;i<NMAT;i++) MatAssemblyEnd(A[i],MAT_FINAL_ASSEMBLY);

127:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
128:                 Create the eigensolver and solve the problem
129:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

131:   PEPCreate(PETSC_COMM_WORLD,&pep);
132:   PEPSetOptionsPrefix(pep,"check_");
133:   PEPAppendOptionsPrefix(pep,"myprefix_");
134:   PEPGetOptionsPrefix(pep,&prefix);
135:   PetscPrintf(PETSC_COMM_WORLD,"PEP prefix is currently: %s\n\n",prefix);

137:   PEPSetOperators(pep,NMAT,A);
138:   PEPSetEigenvalueComparison(pep,MyEigenSort,NULL);
139:   PEPSetFromOptions(pep);
140:   PEPSolve(pep);

142:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
143:                     Display solution and clean up
144:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

146:   /* show detailed info unless -terse option is given by user */
147:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
148:   if (terse) PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
149:   else {
150:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
151:     PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD);
152:     PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
153:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
154:   }
155:   PEPDestroy(&pep);
156:   for (i=0;i<NMAT;i++) MatDestroy(&A[i]);
157:   SlepcFinalize();
158:   return 0;
159: }

161: /*TEST

163:    test:
164:       args: -check_myprefix_pep_nev 4 -terse
165:       requires: double

167: TEST*/