Actual source code: ex43.c

slepc-3.17.0 2022-03-31
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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:   SlepcInitialize(&argc,&argv,(char*)0,help);

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

 42:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 43:      Compute the matrices that define the eigensystem, Ax=kBx
 44:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

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

 56:   MatGetOwnershipRange(A,&Istart,&Iend);
 57:   for (II=Istart;II<Iend;II++) {
 58:     i = II/n; j = II-i*n;
 59:     if (i>0) MatSetValue(A,II,II-n,-1.0,INSERT_VALUES);
 60:     if (i<m-1) MatSetValue(A,II,II+n,-1.0,INSERT_VALUES);
 61:     if (j>0) MatSetValue(A,II,II-1,-1.0,INSERT_VALUES);
 62:     if (j<n-1) MatSetValue(A,II,II+1,-1.0,INSERT_VALUES);
 63:     MatSetValue(A,II,II,4.0,INSERT_VALUES);
 64:     MatSetValue(B,II,II,4.0,INSERT_VALUES);
 65:   }

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

 72:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 73:                 Create the eigensolver and set various options
 74:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

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

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

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

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

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

118:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
119:                       Solve the eigensystem
120:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

122:   EPSSolve(eps);

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

132:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
133:                     Display solution and clean up
134:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

136:   /* show detailed info unless -terse option is given by user */
137:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
138:   if (terse) EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
139:   else {
140:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
141:     EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
142:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
143:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
144:   }
145:   EPSDestroy(&eps);
146:   MatDestroy(&A);
147:   MatDestroy(&B);
148:   SlepcFinalize();
149:   return 0;
150: }

152: /*TEST

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

165: TEST*/