Actual source code: test14.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[] = "Tests a user-defined convergence test in NEP.\n\n"
 12:   "The command line options are:\n"
 13:   "  -n <n>, where <n> = matrix dimension.\n";

 15: /*
 16:    Solve T(lambda)x=0 with T(lambda) = -D+sqrt(lambda)*I
 17:       where D is the Laplacian operator in 1 dimension
 18: */

 20: #include <slepcnep.h>

 22: /*
 23:   MyConvergedRel - Convergence test relative to the norm of D (given in ctx).
 24: */
 25: PetscErrorCode MyConvergedRel(NEP nep,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)
 26: {
 27:   PetscReal norm = *(PetscReal*)ctx;

 29:   *errest = res/norm;
 30:   return 0;
 31: }

 33: int main(int argc,char **argv)
 34: {
 35:   NEP            nep;             /* nonlinear eigensolver context */
 36:   Mat            A[2];
 37:   PetscInt       n=100,Istart,Iend,i;
 38:   PetscBool      terse;
 39:   PetscReal      norm;
 40:   FN             f[2];
 41:   PetscScalar    coeffs;

 44:   SlepcInitialize(&argc,&argv,(char*)0,help);
 45:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 46:   PetscPrintf(PETSC_COMM_WORLD,"\nSquare root eigenproblem, n=%" PetscInt_FMT "\n\n",n);

 48:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 49:      Create nonlinear eigensolver, define problem in split form
 50:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 52:   NEPCreate(PETSC_COMM_WORLD,&nep);

 54:   /* Create matrices */
 55:   MatCreate(PETSC_COMM_WORLD,&A[0]);
 56:   MatSetSizes(A[0],PETSC_DECIDE,PETSC_DECIDE,n,n);
 57:   MatSetFromOptions(A[0]);
 58:   MatSetUp(A[0]);
 59:   MatGetOwnershipRange(A[0],&Istart,&Iend);
 60:   for (i=Istart;i<Iend;i++) {
 61:     if (i>0) MatSetValue(A[0],i,i-1,1.0,INSERT_VALUES);
 62:     if (i<n-1) MatSetValue(A[0],i,i+1,1.0,INSERT_VALUES);
 63:     MatSetValue(A[0],i,i,-2.0,INSERT_VALUES);
 64:   }
 65:   MatAssemblyBegin(A[0],MAT_FINAL_ASSEMBLY);
 66:   MatAssemblyEnd(A[0],MAT_FINAL_ASSEMBLY);

 68:   MatCreateConstantDiagonal(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,n,n,1.0,&A[1]);

 70:   /* Define functions */
 71:   FNCreate(PETSC_COMM_WORLD,&f[0]);
 72:   FNSetType(f[0],FNRATIONAL);
 73:   coeffs = 1.0;
 74:   FNRationalSetNumerator(f[0],1,&coeffs);
 75:   FNCreate(PETSC_COMM_WORLD,&f[1]);
 76:   FNSetType(f[1],FNSQRT);
 77:   NEPSetSplitOperator(nep,2,A,f,SUBSET_NONZERO_PATTERN);

 79:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 80:                    Set some options and solve
 81:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 83:   NEPSetTarget(nep,1.1);

 85:   /* setup convergence test relative to the norm of D */
 86:   MatNorm(A[0],NORM_1,&norm);
 87:   NEPSetConvergenceTestFunction(nep,MyConvergedRel,&norm,NULL);

 89:   NEPSetFromOptions(nep);
 90:   NEPSolve(nep);

 92:   /* show detailed info unless -terse option is given by user */
 93:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
 94:   if (terse) NEPErrorView(nep,NEP_ERROR_BACKWARD,NULL);
 95:   else {
 96:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
 97:     NEPConvergedReasonView(nep,PETSC_VIEWER_STDOUT_WORLD);
 98:     NEPErrorView(nep,NEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
 99:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
100:   }
101:   NEPDestroy(&nep);
102:   MatDestroy(&A[0]);
103:   MatDestroy(&A[1]);
104:   FNDestroy(&f[0]);
105:   FNDestroy(&f[1]);
106:   SlepcFinalize();
107:   return 0;
108: }

110: /*TEST

112:    test:
113:       suffix: 1
114:       args: -nep_type slp -nep_nev 2 -terse

116: TEST*/