Actual source code: test12.c
slepc-3.21.1 2024-04-26
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[] = "Test some NLEIGS interface functions.\n\n"
12: "Based on ex27.c. The command line options are:\n"
13: " -n <n>, where <n> = matrix dimension.\n";
15: /*
16: Solve T(lambda)x=0 using NLEIGS solver
17: with T(lambda) = -D+sqrt(lambda)*I
18: where D is the Laplacian operator in 1 dimension
19: and with the interpolation interval [.01,16]
20: */
22: #include <slepcnep.h>
24: /*
25: User-defined routines
26: */
27: PetscErrorCode ComputeSingularities(NEP,PetscInt*,PetscScalar*,void*);
29: int main(int argc,char **argv)
30: {
31: NEP nep; /* nonlinear eigensolver context */
32: Mat A[2];
33: PetscInt n=100,Istart,Iend,i,ns,nsin;
34: PetscBool terse,fb;
35: RG rg;
36: FN f[2];
37: PetscScalar coeffs,shifts[]={1.06,1.1,1.12,1.15},*rkshifts,val;
38: PetscErrorCode (*fsing)(NEP,PetscInt*,PetscScalar*,void*);
40: PetscFunctionBeginUser;
41: PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
42: PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
43: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nSquare root eigenproblem, n=%" PetscInt_FMT "\n\n",n));
45: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
46: Create nonlinear eigensolver and set some options
47: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
49: PetscCall(NEPCreate(PETSC_COMM_WORLD,&nep));
50: PetscCall(NEPSetType(nep,NEPNLEIGS));
51: PetscCall(NEPNLEIGSSetSingularitiesFunction(nep,ComputeSingularities,NULL));
52: PetscCall(NEPGetRG(nep,&rg));
53: PetscCall(RGSetType(rg,RGINTERVAL));
54: #if defined(PETSC_USE_COMPLEX)
55: PetscCall(RGIntervalSetEndpoints(rg,0.01,16.0,-0.001,0.001));
56: #else
57: PetscCall(RGIntervalSetEndpoints(rg,0.01,16.0,0,0));
58: #endif
59: PetscCall(NEPSetTarget(nep,1.1));
61: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
62: Define the nonlinear problem in split form
63: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
65: /* Create matrices */
66: PetscCall(MatCreate(PETSC_COMM_WORLD,&A[0]));
67: PetscCall(MatSetSizes(A[0],PETSC_DECIDE,PETSC_DECIDE,n,n));
68: PetscCall(MatSetFromOptions(A[0]));
69: PetscCall(MatGetOwnershipRange(A[0],&Istart,&Iend));
70: for (i=Istart;i<Iend;i++) {
71: if (i>0) PetscCall(MatSetValue(A[0],i,i-1,1.0,INSERT_VALUES));
72: if (i<n-1) PetscCall(MatSetValue(A[0],i,i+1,1.0,INSERT_VALUES));
73: PetscCall(MatSetValue(A[0],i,i,-2.0,INSERT_VALUES));
74: }
75: PetscCall(MatAssemblyBegin(A[0],MAT_FINAL_ASSEMBLY));
76: PetscCall(MatAssemblyEnd(A[0],MAT_FINAL_ASSEMBLY));
78: PetscCall(MatCreateConstantDiagonal(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,n,n,1.0,&A[1]));
80: /* Define functions */
81: PetscCall(FNCreate(PETSC_COMM_WORLD,&f[0]));
82: PetscCall(FNSetType(f[0],FNRATIONAL));
83: coeffs = 1.0;
84: PetscCall(FNRationalSetNumerator(f[0],1,&coeffs));
85: PetscCall(FNCreate(PETSC_COMM_WORLD,&f[1]));
86: PetscCall(FNSetType(f[1],FNSQRT));
87: PetscCall(NEPSetSplitOperator(nep,2,A,f,SUBSET_NONZERO_PATTERN));
89: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
90: Set some options
91: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
93: PetscCall(NEPNLEIGSSetFullBasis(nep,PETSC_FALSE));
94: PetscCall(NEPNLEIGSSetRKShifts(nep,4,shifts));
95: PetscCall(NEPSetFromOptions(nep));
97: PetscCall(NEPNLEIGSGetFullBasis(nep,&fb));
98: PetscCall(PetscPrintf(PETSC_COMM_WORLD," Using full basis = %s\n",fb?"true":"false"));
99: PetscCall(NEPNLEIGSGetRKShifts(nep,&ns,&rkshifts));
100: if (ns) {
101: PetscCall(PetscPrintf(PETSC_COMM_WORLD," Using %" PetscInt_FMT " RK shifts =",ns));
102: for (i=0;i<ns;i++) PetscCall(PetscPrintf(PETSC_COMM_WORLD," %g",(double)PetscRealPart(rkshifts[i])));
103: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n"));
104: PetscCall(PetscFree(rkshifts));
105: }
106: PetscCall(NEPNLEIGSGetSingularitiesFunction(nep,&fsing,NULL));
107: nsin = 1;
108: PetscCall((*fsing)(nep,&nsin,&val,NULL));
109: PetscCall(PetscPrintf(PETSC_COMM_WORLD," First returned singularity = %g\n",(double)PetscRealPart(val)));
111: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
112: Solve the eigensystem
113: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
114: PetscCall(NEPSolve(nep));
116: /* show detailed info unless -terse option is given by user */
117: PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
118: if (terse) PetscCall(NEPErrorView(nep,NEP_ERROR_BACKWARD,NULL));
119: else {
120: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
121: PetscCall(NEPConvergedReasonView(nep,PETSC_VIEWER_STDOUT_WORLD));
122: PetscCall(NEPErrorView(nep,NEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
123: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
124: }
125: PetscCall(NEPDestroy(&nep));
126: PetscCall(MatDestroy(&A[0]));
127: PetscCall(MatDestroy(&A[1]));
128: PetscCall(FNDestroy(&f[0]));
129: PetscCall(FNDestroy(&f[1]));
130: PetscCall(SlepcFinalize());
131: return 0;
132: }
134: /* ------------------------------------------------------------------- */
135: /*
136: ComputeSingularities - Computes maxnp points (at most) in the complex plane where
137: the function T(.) is not analytic.
139: In this case, we discretize the singularity region (-inf,0)~(-10e+6,-10e-6)
140: */
141: PetscErrorCode ComputeSingularities(NEP nep,PetscInt *maxnp,PetscScalar *xi,void *pt)
142: {
143: PetscReal h;
144: PetscInt i;
146: PetscFunctionBeginUser;
147: h = 11.0/(*maxnp-1);
148: xi[0] = -1e-5; xi[*maxnp-1] = -1e+6;
149: for (i=1;i<*maxnp-1;i++) xi[i] = -PetscPowReal(10,-5+h*i);
150: PetscFunctionReturn(PETSC_SUCCESS);
151: }
153: /*TEST
155: test:
156: suffix: 1
157: args: -nep_nev 3 -nep_nleigs_interpolation_degree 20 -terse -nep_view
158: requires: double
159: filter: grep -v tolerance | sed -e "s/[+-]0\.0*i//g"
161: TEST*/