Actual source code: test13.c
slepc-3.13.1 2020-04-12
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2020, 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;
38: PetscErrorCode ierr;
40: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
41: PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
42: PetscOptionsGetInt(NULL,NULL,"-n",&n,&flg);
43: if (!flg) n=m+2;
44: PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
45: PetscPrintf(PETSC_COMM_WORLD,"\nRectangular bidiagonal matrix, m=%D n=%D\n\n",m,n);
47: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
48: Generate the matrix
49: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
51: MatCreate(PETSC_COMM_WORLD,&A);
52: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,m,n);
53: MatSetFromOptions(A);
54: MatSetUp(A);
55: MatGetOwnershipRange(A,&Istart,&Iend);
56: for (i=Istart;i<Iend;i++) {
57: col[0]=i; col[1]=i+1;
58: if (i<n-1) {
59: MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);
60: } else if (i==n-1) {
61: MatSetValue(A,i,col[0],value[0],INSERT_VALUES);
62: }
63: }
64: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
65: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
67: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
68: Compute singular values
69: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
71: SVDCreate(PETSC_COMM_WORLD,&svd);
72: SVDSetOperator(svd,A);
73: SVDSetType(svd,SVDPRIMME);
74: SVDPRIMMESetBlockSize(svd,4);
75: SVDPRIMMESetMethod(svd,SVD_PRIMME_HYBRID);
76: SVDSetFromOptions(svd);
78: SVDSolve(svd);
79: SVDPRIMMEGetBlockSize(svd,&bs);
80: SVDPRIMMEGetMethod(svd,&meth);
81: PetscPrintf(PETSC_COMM_WORLD," PRIMME: using block size %D, method %s\n",bs,SVDPRIMMEMethods[meth]);
83: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
84: Display solution and clean up
85: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
86: SVDErrorView(svd,SVD_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
87: SVDDestroy(&svd);
88: MatDestroy(&A);
89: SlepcFinalize();
90: return ierr;
91: }
93: /*TEST
95: build:
96: requires: primme
98: test:
99: suffix: 1
100: args: -svd_nsv 4
101: requires: primme
103: TEST*/