Actual source code: test18.c
slepc-3.18.2 2023-01-26
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 GSVD with user-provided initial vectors.\n\n"
12: "The command line options are:\n"
13: " -m <m>, where <m> = number of rows of A.\n"
14: " -n <n>, where <n> = number of columns of A.\n"
15: " -p <p>, where <p> = number of rows of B.\n\n";
17: #include <slepcsvd.h>
19: /*
20: This example solves a GSVD problem for the bidiagonal matrices
22: | 1 2 | | 2 |
23: | 1 2 | | -1 2 |
24: | 1 2 | | -1 2 |
25: A = | . . | B = | . . |
26: | . . | | . . |
27: | 1 2 | | -1 2 |
28: | 1 2 | | -1 2 |
29: */
31: int main(int argc,char **argv)
32: {
33: Mat A,B;
34: SVD svd;
35: Vec v0,w0; /* initial vectors */
36: VecType vtype;
37: PetscInt m=22,n=20,p=22,Istart,Iend,i,col[2];
38: PetscScalar valsa[] = { 1, 2 }, valsb[] = { -1, 2 };
41: SlepcInitialize(&argc,&argv,(char*)0,help);
42: PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
43: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
44: PetscOptionsGetInt(NULL,NULL,"-p",&p,NULL);
45: PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized singular value decomposition, (%" PetscInt_FMT "+%" PetscInt_FMT ")x%" PetscInt_FMT "\n\n",m,p,n);
47: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
48: Generate the matrices
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) MatSetValues(A,1,&i,2,col,valsa,INSERT_VALUES);
59: else if (i==n-1) MatSetValue(A,i,col[0],valsa[0],INSERT_VALUES);
60: }
61: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
62: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
64: MatCreate(PETSC_COMM_WORLD,&B);
65: MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,m,n);
66: MatSetFromOptions(B);
67: MatSetUp(B);
68: MatGetOwnershipRange(B,&Istart,&Iend);
69: for (i=Istart;i<Iend;i++) {
70: col[0]=i-1; col[1]=i;
71: if (i==0) MatSetValue(B,i,col[1],valsb[1],INSERT_VALUES);
72: else if (i<n) MatSetValues(B,1,&i,2,col,valsb,INSERT_VALUES);
73: else if (i==n) MatSetValue(B,i,col[0],valsb[0],INSERT_VALUES);
74: }
75: MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
76: MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
78: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
79: Create the singular value solver, set options and solve
80: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
82: SVDCreate(PETSC_COMM_WORLD,&svd);
83: SVDSetOperators(svd,A,B);
84: SVDSetFromOptions(svd);
86: /*
87: Set the initial vectors. This is optional, if not done the initial
88: vectors are set to random values
89: */
90: MatCreateVecs(A,&v0,NULL); /* right initial vector, length n */
91: VecCreate(PETSC_COMM_WORLD,&w0); /* left initial vector, length m+p */
92: VecSetSizes(w0,PETSC_DECIDE,m+p);
93: VecGetType(v0,&vtype);
94: VecSetType(w0,vtype);
95: VecSet(v0,1.0);
96: VecSet(w0,1.0);
97: SVDSetInitialSpaces(svd,1,&v0,1,&w0);
99: /*
100: Compute solution
101: */
102: SVDSolve(svd);
103: SVDErrorView(svd,SVD_ERROR_NORM,NULL);
105: /* Free work space */
106: VecDestroy(&v0);
107: VecDestroy(&w0);
108: SVDDestroy(&svd);
109: MatDestroy(&A);
110: MatDestroy(&B);
111: SlepcFinalize();
112: return 0;
113: }
115: /*TEST
117: testset:
118: args: -svd_nsv 3
119: requires: !single
120: output_file: output/test18_1.out
121: test:
122: suffix: 1
123: args: -svd_type {{lapack cross cyclic}}
124: test:
125: suffix: 1_trlanczos
126: args: -svd_type trlanczos -svd_trlanczos_gbidiag {{single upper lower}}
127: requires: !__float128
129: test:
130: suffix: 2
131: args: -svd_nsv 3 -svd_type trlanczos -svd_monitor_conditioning
132: requires: double
134: TEST*/