Actual source code: test41.c
slepc-3.18.0 2022-10-01
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 interface to external package EVSL.\n\n"
12: "This is based on ex3.c. The command line options are:\n"
13: " -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
14: " -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";
16: #include <slepceps.h>
18: int main(int argc,char **argv)
19: {
20: Mat A; /* matrix */
21: EPS eps; /* eigenproblem solver context */
22: PetscInt N,n=20,m,Istart,Iend,II,i,j,nslice;
23: PetscReal a,b,ra,rb;
24: PetscBool flag;
25: EPSEVSLDamping damping;
28: SlepcInitialize(&argc,&argv,(char*)0,help);
30: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
31: PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
32: if (!flag) m=n;
33: N = n*m;
34: PetscPrintf(PETSC_COMM_WORLD,"\nStandard eigenproblem with EVSL, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m);
36: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
37: Compute the matrices that define the eigensystem, Ax=kBx
38: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
40: MatCreate(PETSC_COMM_WORLD,&A);
41: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
42: MatSetFromOptions(A);
43: MatSetUp(A);
45: MatGetOwnershipRange(A,&Istart,&Iend);
46: for (II=Istart;II<Iend;II++) {
47: i = II/n; j = II-i*n;
48: if (i>0) MatSetValue(A,II,II-n,-1.0,INSERT_VALUES);
49: if (i<m-1) MatSetValue(A,II,II+n,-1.0,INSERT_VALUES);
50: if (j>0) MatSetValue(A,II,II-1,-1.0,INSERT_VALUES);
51: if (j<n-1) MatSetValue(A,II,II+1,-1.0,INSERT_VALUES);
52: MatSetValue(A,II,II,4.0,INSERT_VALUES);
53: }
55: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
56: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
58: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
59: Create the eigensolver and set various options
60: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
62: EPSCreate(PETSC_COMM_WORLD,&eps);
63: EPSSetOperators(eps,A,NULL);
64: EPSSetProblemType(eps,EPS_HEP);
65: EPSSetType(eps,EPSEVSL);
67: /*
68: Set several options
69: */
70: EPSSetInterval(eps,1.3,1.44);
71: EPSEVSLSetRange(eps,0,8);
72: EPSEVSLSetSlices(eps,3);
73: EPSEVSLSetDamping(eps,EPS_EVSL_DAMPING_SIGMA);
74: EPSEVSLSetDOSParameters(eps,EPS_EVSL_DOS_KPM,50,450,PETSC_DEFAULT,PETSC_DEFAULT);
75: EPSEVSLSetPolParameters(eps,4000,0.85);
76: EPSSetFromOptions(eps);
78: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
79: Compute all eigenvalues in interval and display info
80: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
82: EPSSolve(eps);
83: EPSEVSLGetSlices(eps,&nslice);
84: EPSGetInterval(eps,&a,&b);
85: EPSEVSLGetRange(eps,&ra,&rb);
86: PetscPrintf(PETSC_COMM_WORLD," EVSL: solving interval [%g,%g] with %" PetscInt_FMT " slices (spectral range [%g,%g])\n",a,b,nslice,ra,rb);
87: EPSEVSLGetDamping(eps,&damping);
88: PetscPrintf(PETSC_COMM_WORLD," EVSL: damping type is %s\n",EPSEVSLDampings[damping]);
90: EPSView(eps,NULL);
91: EPSErrorView(eps,EPS_ERROR_ABSOLUTE,NULL);
93: EPSDestroy(&eps);
94: MatDestroy(&A);
95: SlepcFinalize();
96: return 0;
97: }
99: /*TEST
101: build:
102: requires: evsl
104: test:
105: requires: evsl
106: args: -eps_evsl_damping none
107: filter: grep -v ncv
109: TEST*/