Actual source code: test13.c
slepc-3.20.1 2023-11-27
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 PRIMME.\n\n"
12: "The command line options are:\n"
13: " -m <m>, where <m> = matrix rows.\n"
14: " -n <n>, where <n> = matrix columns (defaults to m+2).\n\n";
16: #include <slepcsvd.h>
18: /*
19: This example computes the singular values of a rectangular bidiagonal matrix
21: | 1 2 |
22: | 1 2 |
23: | 1 2 |
24: A = | . . |
25: | . . |
26: | 1 2 |
27: | 1 2 |
28: */
30: int main(int argc,char **argv)
31: {
32: Mat A;
33: SVD svd;
34: PetscInt m=20,n,Istart,Iend,i,k=6,col[2],bs;
35: PetscScalar value[] = { 1, 2 };
36: PetscBool flg;
37: SVDPRIMMEMethod meth;
39: PetscFunctionBeginUser;
40: PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
41: PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL));
42: PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,&flg));
43: if (!flg) n=m+2;
44: PetscCall(PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL));
45: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nRectangular bidiagonal matrix, m=%" PetscInt_FMT " n=%" PetscInt_FMT "\n\n",m,n));
47: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
48: Generate the matrix
49: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
51: PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
52: PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,m,n));
53: PetscCall(MatSetFromOptions(A));
54: PetscCall(MatSetUp(A));
55: PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
56: for (i=Istart;i<Iend;i++) {
57: col[0]=i; col[1]=i+1;
58: if (i<n-1) PetscCall(MatSetValues(A,1,&i,2,col,value,INSERT_VALUES));
59: else if (i==n-1) PetscCall(MatSetValue(A,i,col[0],value[0],INSERT_VALUES));
60: }
61: PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
62: PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));
64: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
65: Compute singular values
66: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
68: PetscCall(SVDCreate(PETSC_COMM_WORLD,&svd));
69: PetscCall(SVDSetOperators(svd,A,NULL));
70: PetscCall(SVDSetType(svd,SVDPRIMME));
71: PetscCall(SVDPRIMMESetBlockSize(svd,4));
72: PetscCall(SVDPRIMMESetMethod(svd,SVD_PRIMME_HYBRID));
73: PetscCall(SVDSetFromOptions(svd));
75: PetscCall(SVDSolve(svd));
76: PetscCall(SVDPRIMMEGetBlockSize(svd,&bs));
77: PetscCall(SVDPRIMMEGetMethod(svd,&meth));
78: PetscCall(PetscPrintf(PETSC_COMM_WORLD," PRIMME: using block size %" PetscInt_FMT ", method %s\n",bs,SVDPRIMMEMethods[meth]));
80: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
81: Display solution and clean up
82: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
83: PetscCall(SVDErrorView(svd,SVD_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
84: PetscCall(SVDDestroy(&svd));
85: PetscCall(MatDestroy(&A));
86: PetscCall(SlepcFinalize());
87: return 0;
88: }
90: /*TEST
92: build:
93: requires: primme
95: test:
96: suffix: 1
97: nsize: 2
98: args: -svd_nsv 4
99: requires: primme
100: filter: sed -e "s/2.99255/2.99254/" | sed -e "s/2.97024/2.97023/"
102: TEST*/