Actual source code: ex43.c

slepc-3.21.1 2024-04-26
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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[] = "Generalized eigenproblem, illustrates setting MUMPS options.\n\n"
 12:   "The problem is Ax = lambda Bx, with:\n"
 13:   "   A = Laplacian operator in 2-D\n"
 14:   "   B = diagonal matrix with all values equal to 4\n\n"
 15:   "The command line options are:\n"
 16:   "  -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
 17:   "  -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";

 19: #include <slepceps.h>

 21: int main(int argc,char **argv)
 22: {
 23:   Mat            A,B;
 24: #if defined(PETSC_HAVE_MUMPS)
 25:   Mat            K;
 26: #endif
 27:   EPS            eps;
 28:   EPSType        type;
 29:   ST             st;
 30:   KSP            ksp;
 31:   PC             pc;
 32:   PetscInt       N,n=10,m=12,Istart,Iend,II,nev,i,j;
 33:   PetscBool      flag,terse;

 35:   PetscFunctionBeginUser;
 36:   PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));

 38:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
 39:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag));
 40:   N = n*m;
 41:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m));

 43:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 44:      Compute the matrices that define the eigensystem, Ax=kBx
 45:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 47:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
 48:   PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N));
 49:   PetscCall(MatSetFromOptions(A));

 51:   PetscCall(MatCreate(PETSC_COMM_WORLD,&B));
 52:   PetscCall(MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N));
 53:   PetscCall(MatSetFromOptions(B));

 55:   PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
 56:   for (II=Istart;II<Iend;II++) {
 57:     i = II/n; j = II-i*n;
 58:     if (i>0) PetscCall(MatSetValue(A,II,II-n,-1.0,INSERT_VALUES));
 59:     if (i<m-1) PetscCall(MatSetValue(A,II,II+n,-1.0,INSERT_VALUES));
 60:     if (j>0) PetscCall(MatSetValue(A,II,II-1,-1.0,INSERT_VALUES));
 61:     if (j<n-1) PetscCall(MatSetValue(A,II,II+1,-1.0,INSERT_VALUES));
 62:     PetscCall(MatSetValue(A,II,II,4.0,INSERT_VALUES));
 63:     PetscCall(MatSetValue(B,II,II,4.0,INSERT_VALUES));
 64:   }

 66:   PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
 67:   PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));
 68:   PetscCall(MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY));
 69:   PetscCall(MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY));

 71:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 72:                 Create the eigensolver and set various options
 73:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 75:   /*
 76:      Create eigensolver context
 77:   */
 78:   PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));

 80:   /*
 81:      Set operators. In this case, it is a generalized eigenvalue problem
 82:   */
 83:   PetscCall(EPSSetOperators(eps,A,B));
 84:   PetscCall(EPSSetProblemType(eps,EPS_GNHEP));

 86:   /*
 87:      Set some solver options
 88:   */
 89:   PetscCall(EPSSetTarget(eps,1.3));
 90:   PetscCall(EPSSetDimensions(eps,2,PETSC_DEFAULT,PETSC_DEFAULT));
 91:   PetscCall(EPSGetST(eps,&st));
 92:   PetscCall(STSetType(st,STSINVERT));

 94:   PetscCall(STGetKSP(st,&ksp));
 95:   PetscCall(KSPSetType(ksp,KSPPREONLY));
 96:   PetscCall(KSPGetPC(ksp,&pc));
 97:   PetscCall(PCSetType(pc,PCLU));

 99:   /*
100:      Set MUMPS options if available
101:   */
102: #if defined(PETSC_HAVE_MUMPS)
103:   PetscCall(PCFactorSetMatSolverType(pc,MATSOLVERMUMPS));
104:   /* the next line is required to force the creation of the ST operator and its passing to KSP */
105:   PetscCall(STGetOperator(st,NULL));
106:   PetscCall(PCFactorSetUpMatSolverType(pc));
107:   PetscCall(PCFactorGetMatrix(pc,&K));
108:   PetscCall(MatMumpsSetIcntl(K,14,50));
109:   PetscCall(MatMumpsSetCntl(K,3,1e-12));
110: #endif

112:   /*
113:      Let the user change settings at runtime
114:   */
115:   PetscCall(EPSSetFromOptions(eps));

117:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
118:                       Solve the eigensystem
119:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

121:   PetscCall(EPSSolve(eps));

123:   /*
124:      Optional: Get some information from the solver and display it
125:   */
126:   PetscCall(EPSGetType(eps,&type));
127:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type));
128:   PetscCall(EPSGetDimensions(eps,&nev,NULL,NULL));
129:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev));

131:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
132:                     Display solution and clean up
133:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

135:   /* show detailed info unless -terse option is given by user */
136:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
137:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
138:   else {
139:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
140:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
141:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
142:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
143:   }
144:   PetscCall(EPSDestroy(&eps));
145:   PetscCall(MatDestroy(&A));
146:   PetscCall(MatDestroy(&B));
147:   PetscCall(SlepcFinalize());
148:   return 0;
149: }

151: /*TEST

153:    testset:
154:       args: -terse
155:       output_file: output/ex43_1.out
156:       test:
157:          suffix: 1
158:       test:
159:          suffix: 2
160:          nsize: 2
161:          args: -st_pc_factor_mat_solver_type mumps
162:          requires: mumps

164: TEST*/