Actual source code: test14.c

slepc-3.15.0 2021-03-31
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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[] = "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;

 30:   *errest = res/norm;
 31:   return(0);
 32: }

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

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

 49:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 50:      Create nonlinear eigensolver, define problem in split form
 51:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 53:   NEPCreate(PETSC_COMM_WORLD,&nep);

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

 69:   MatCreate(PETSC_COMM_WORLD,&A[1]);
 70:   MatSetSizes(A[1],PETSC_DECIDE,PETSC_DECIDE,n,n);
 71:   MatSetFromOptions(A[1]);
 72:   MatSetUp(A[1]);
 73:   MatAssemblyBegin(A[1],MAT_FINAL_ASSEMBLY);
 74:   MatAssemblyEnd(A[1],MAT_FINAL_ASSEMBLY);
 75:   MatShift(A[1],1.0);

 77:   /* Define functions */
 78:   FNCreate(PETSC_COMM_WORLD,&f[0]);
 79:   FNSetType(f[0],FNRATIONAL);
 80:   coeffs = 1.0;
 81:   FNRationalSetNumerator(f[0],1,&coeffs);
 82:   FNCreate(PETSC_COMM_WORLD,&f[1]);
 83:   FNSetType(f[1],FNSQRT);
 84:   NEPSetSplitOperator(nep,2,A,f,SUBSET_NONZERO_PATTERN);

 86:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 87:                    Set some options and solve
 88:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 90:   NEPSetTarget(nep,1.1);

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

 96:   NEPSetFromOptions(nep);
 97:   NEPSolve(nep);

 99:   /* show detailed info unless -terse option is given by user */
100:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
101:   if (terse) {
102:     NEPErrorView(nep,NEP_ERROR_BACKWARD,NULL);
103:   } else {
104:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
105:     NEPConvergedReasonView(nep,PETSC_VIEWER_STDOUT_WORLD);
106:     NEPErrorView(nep,NEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD);
107:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
108:   }
109:   NEPDestroy(&nep);
110:   MatDestroy(&A[0]);
111:   MatDestroy(&A[1]);
112:   FNDestroy(&f[0]);
113:   FNDestroy(&f[1]);
114:   SlepcFinalize();
115:   return ierr;
116: }

118: /*TEST

120:    test:
121:       suffix: 1
122:       args: -nep_type slp -nep_nev 2 -terse

124: TEST*/