Actual source code: ex43.c

slepc-3.16.0 2021-09-30
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2021, 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;

 36:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;

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

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

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

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

 57:   MatGetOwnershipRange(A,&Istart,&Iend);
 58:   for (II=Istart;II<Iend;II++) {
 59:     i = II/n; j = II-i*n;
 60:     if (i>0) { MatSetValue(A,II,II-n,-1.0,INSERT_VALUES); }
 61:     if (i<m-1) { MatSetValue(A,II,II+n,-1.0,INSERT_VALUES); }
 62:     if (j>0) { MatSetValue(A,II,II-1,-1.0,INSERT_VALUES); }
 63:     if (j<n-1) { MatSetValue(A,II,II+1,-1.0,INSERT_VALUES); }
 64:     MatSetValue(A,II,II,4.0,INSERT_VALUES);
 65:     MatSetValue(B,II,II,4.0,INSERT_VALUES);
 66:   }

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

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

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

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

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

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

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

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

119:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
120:                       Solve the eigensystem
121:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

123:   EPSSolve(eps);

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

133:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
134:                     Display solution and clean up
135:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

137:   /* show detailed info unless -terse option is given by user */
138:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
139:   if (terse) {
140:     EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
141:   } else {
142:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
143:     EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
144:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
145:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
146:   }
147:   EPSDestroy(&eps);
148:   MatDestroy(&A);
149:   MatDestroy(&B);
150:   SlepcFinalize();
151:   return ierr;
152: }

154: /*TEST

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

167: TEST*/