Actual source code: test10.c
slepc-3.11.2 2019-07-30
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2019, 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 Phi functions.\n\n";
13: #include <slepcfn.h>
15: /*
16: Evaluates phi_k function on a scalar and on a matrix
17: */
18: PetscErrorCode TestPhiFunction(FN fn,PetscScalar x,Mat A,PetscBool verbose)
19: {
21: PetscScalar y,yp;
22: char strx[50],str[50];
23: Vec v,f;
24: PetscReal nrm;
27: PetscPrintf(PETSC_COMM_WORLD,"\n");
28: FNView(fn,NULL);
29: SlepcSNPrintfScalar(strx,50,x,PETSC_FALSE);
30: FNEvaluateFunction(fn,x,&y);
31: FNEvaluateDerivative(fn,x,&yp);
32: SlepcSNPrintfScalar(str,50,y,PETSC_FALSE);
33: PetscPrintf(PETSC_COMM_WORLD,"\nf(%s)=%s\n",strx,str);
34: SlepcSNPrintfScalar(str,50,yp,PETSC_FALSE);
35: PetscPrintf(PETSC_COMM_WORLD,"f'(%s)=%s\n",strx,str);
36: /* compute phi_k(A)*e_1 */
37: MatCreateVecs(A,&v,&f);
38: MatSetOption(A,MAT_HERMITIAN,PETSC_TRUE);
39: FNEvaluateFunctionMatVec(fn,A,f); /* reference result by diagonalization */
40: MatSetOption(A,MAT_HERMITIAN,PETSC_FALSE);
41: FNEvaluateFunctionMatVec(fn,A,v);
42: VecAXPY(v,-1.0,f);
43: VecNorm(v,NORM_2,&nrm);
44: if (nrm>100*PETSC_MACHINE_EPSILON) {
45: PetscPrintf(PETSC_COMM_WORLD,"Warning: the norm of f(A)*e_1-ref is %g\n",(double)nrm);
46: }
47: if (verbose) {
48: PetscPrintf(PETSC_COMM_WORLD,"f(A)*e_1 =\n");
49: VecView(v,NULL);
50: }
51: VecDestroy(&v);
52: VecDestroy(&f);
53: return(0);
54: }
56: int main(int argc,char **argv)
57: {
59: FN phi0,phi1,phik,phicopy;
60: Mat A;
61: PetscInt i,j,n=8,k;
62: PetscScalar tau,eta,*As;
63: PetscBool verbose;
65: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
66: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
67: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
68: PetscPrintf(PETSC_COMM_WORLD,"Test Phi functions, n=%D.\n",n);
70: /* Create matrix, fill it with 1-D Laplacian */
71: MatCreateSeqDense(PETSC_COMM_SELF,n,n,NULL,&A);
72: PetscObjectSetName((PetscObject)A,"A");
73: MatDenseGetArray(A,&As);
74: for (i=0;i<n;i++) As[i+i*n]=2.0;
75: j=1;
76: for (i=0;i<n-j;i++) { As[i+(i+j)*n]=-1.0; As[(i+j)+i*n]=-1.0; }
77: MatDenseRestoreArray(A,&As);
79: /* phi_0(x) = exp(x) */
80: FNCreate(PETSC_COMM_WORLD,&phi0);
81: FNSetType(phi0,FNPHI);
82: FNPhiSetIndex(phi0,0);
83: TestPhiFunction(phi0,2.2,A,verbose);
85: /* phi_1(x) = (exp(x)-1)/x with scaling factors eta*phi_1(tau*x) */
86: FNCreate(PETSC_COMM_WORLD,&phi1);
87: FNSetType(phi1,FNPHI); /* default index should be 1 */
88: tau = 0.2;
89: eta = 1.3;
90: FNSetScale(phi1,tau,eta);
91: TestPhiFunction(phi1,2.2,A,verbose);
93: /* phi_k(x) with index set from command-line arguments */
94: FNCreate(PETSC_COMM_WORLD,&phik);
95: FNSetType(phik,FNPHI);
96: FNSetFromOptions(phik);
98: FNDuplicate(phik,PETSC_COMM_WORLD,&phicopy);
99: FNPhiGetIndex(phicopy,&k);
100: PetscPrintf(PETSC_COMM_WORLD,"Index of phi function is %D\n",k);
101: TestPhiFunction(phicopy,2.2,A,verbose);
103: FNDestroy(&phi0);
104: FNDestroy(&phi1);
105: FNDestroy(&phik);
106: FNDestroy(&phicopy);
107: MatDestroy(&A);
108: SlepcFinalize();
109: return ierr;
110: }
112: /*TEST
114: test:
115: suffix: 1
116: nsize: 1
117: args: -fn_phi_index 3
119: TEST*/