Actual source code: test21.c
slepc-3.16.2 2022-02-01
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[] = "Illustrates region filtering. "
12: "Based on ex5.\n"
13: "The command line options are:\n"
14: " -m <m>, where <m> = number of grid subdivisions in each dimension.\n\n";
16: #include <slepceps.h>
18: /*
19: User-defined routines
20: */
21: PetscErrorCode MatMarkovModel(PetscInt m,Mat A);
23: int main(int argc,char **argv)
24: {
25: Mat A;
26: EPS eps;
27: ST st;
28: RG rg;
29: PetscReal radius,tol=PETSC_SMALL;
30: PetscScalar target=0.5,kr,ki;
31: PetscComplex *eigs,eval;
32: PetscInt N,m=15,nev,i,nconv;
33: PetscBool checkfile;
34: char filename[PETSC_MAX_PATH_LEN];
35: PetscViewer viewer;
37: char str[50];
39: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
40: #if defined(PETSC_HAVE_COMPLEX)
41: PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
42: N = m*(m+1)/2;
43: PetscPrintf(PETSC_COMM_WORLD,"\nMarkov Model, N=%D (m=%D)\n",N,m);
44: PetscOptionsGetScalar(NULL,NULL,"-target",&target,NULL);
45: SlepcSNPrintfScalar(str,sizeof(str),target,PETSC_FALSE);
46: PetscPrintf(PETSC_COMM_WORLD,"Searching closest eigenvalues to the right of %s.\n\n",str);
48: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
49: Compute the operator matrix that defines the eigensystem, Ax=kx
50: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
52: MatCreate(PETSC_COMM_WORLD,&A);
53: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
54: MatSetFromOptions(A);
55: MatSetUp(A);
56: MatMarkovModel(m,A);
58: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
59: Create a standalone spectral transformation
60: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
62: STCreate(PETSC_COMM_WORLD,&st);
63: STSetType(st,STSINVERT);
64: STSetShift(st,target);
66: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
67: Create a region for filtering
68: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
70: RGCreate(PETSC_COMM_WORLD,&rg);
71: RGSetType(rg,RGELLIPSE);
72: radius = (1.0-PetscRealPart(target))/2.0;
73: RGEllipseSetParameters(rg,target+radius,radius,0.1);
75: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
76: Create the eigensolver and set various options
77: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
79: EPSCreate(PETSC_COMM_WORLD,&eps);
80: EPSSetST(eps,st);
81: EPSSetRG(eps,rg);
82: EPSSetOperators(eps,A,NULL);
83: EPSSetProblemType(eps,EPS_NHEP);
84: EPSSetTolerances(eps,tol,PETSC_DEFAULT);
85: EPSSetTarget(eps,target);
86: EPSSetFromOptions(eps);
88: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
89: Solve the eigensystem and display solution
90: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
92: EPSSolve(eps);
93: EPSGetDimensions(eps,&nev,NULL,NULL);
94: PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);
95: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
97: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
98: Check file containing the eigenvalues
99: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
100: PetscOptionsGetString(NULL,NULL,"-checkfile",filename,sizeof(filename),&checkfile);
101: if (checkfile) {
102: EPSGetConverged(eps,&nconv);
103: PetscMalloc1(nconv,&eigs);
104: PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
105: PetscViewerBinaryRead(viewer,eigs,nconv,NULL,PETSC_COMPLEX);
106: PetscViewerDestroy(&viewer);
107: for (i=0;i<nconv;i++) {
108: EPSGetEigenpair(eps,i,&kr,&ki,NULL,NULL);
109: #if defined(PETSC_USE_COMPLEX)
110: eval = kr;
111: #else
112: eval = PetscCMPLX(kr,ki);
113: #endif
114: if (eval!=eigs[i]) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_FILE_UNEXPECTED,"Eigenvalues in the file do not match");
115: }
116: PetscFree(eigs);
117: }
119: EPSDestroy(&eps);
120: STDestroy(&st);
121: RGDestroy(&rg);
122: MatDestroy(&A);
123: #else
124: SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"This example requires C99 complex numbers");
125: #endif
126: SlepcFinalize();
127: return ierr;
128: }
130: PetscErrorCode MatMarkovModel(PetscInt m,Mat A)
131: {
132: const PetscReal cst = 0.5/(PetscReal)(m-1);
133: PetscReal pd,pu;
134: PetscInt Istart,Iend,i,j,jmax,ix=0;
135: PetscErrorCode ierr;
138: MatGetOwnershipRange(A,&Istart,&Iend);
139: for (i=1;i<=m;i++) {
140: jmax = m-i+1;
141: for (j=1;j<=jmax;j++) {
142: ix = ix + 1;
143: if (ix-1<Istart || ix>Iend) continue; /* compute only owned rows */
144: if (j!=jmax) {
145: pd = cst*(PetscReal)(i+j-1);
146: /* north */
147: if (i==1) {
148: MatSetValue(A,ix-1,ix,2*pd,INSERT_VALUES);
149: } else {
150: MatSetValue(A,ix-1,ix,pd,INSERT_VALUES);
151: }
152: /* east */
153: if (j==1) {
154: MatSetValue(A,ix-1,ix+jmax-1,2*pd,INSERT_VALUES);
155: } else {
156: MatSetValue(A,ix-1,ix+jmax-1,pd,INSERT_VALUES);
157: }
158: }
159: /* south */
160: pu = 0.5 - cst*(PetscReal)(i+j-3);
161: if (j>1) {
162: MatSetValue(A,ix-1,ix-2,pu,INSERT_VALUES);
163: }
164: /* west */
165: if (i>1) {
166: MatSetValue(A,ix-1,ix-jmax-2,pu,INSERT_VALUES);
167: }
168: }
169: }
170: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
171: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
172: return(0);
173: }
175: /*TEST
177: test:
178: suffix: 1
179: args: -eps_nev 4 -eps_ncv 20 -eps_view_values binary:myvalues.bin -checkfile myvalues.bin
180: output_file: output/test11_1.out
181: requires: !single c99_complex
183: TEST*/