sbdt05.f - Man Page
TESTING/EIG/sbdt05.f
Synopsis
Functions/Subroutines
subroutine sbdt05 (m, n, a, lda, s, ns, u, ldu, vt, ldvt, work, resid)
SBDT05
Function/Subroutine Documentation
subroutine sbdt05 (integer m, integer n, real, dimension( lda, * ) a, integer lda, real, dimension( * ) s, integer ns, real, dimension( ldu, * ) u, integer ldu, real, dimension( ldvt, * ) vt, integer ldvt, real, dimension( * ) work, real resid)
SBDT05
Purpose:
SBDT05 reconstructs a bidiagonal matrix B from its (partial) SVD: S = U' * B * V where U and V are orthogonal matrices and S is diagonal. The test ratio to test the singular value decomposition is RESID = norm( S - U' * B * V ) / ( n * norm(B) * EPS ) where VT = V' and EPS is the machine precision.
- Parameters
M
M is INTEGER The number of rows of the matrices A and U.
N
N is INTEGER The number of columns of the matrices A and VT.
A
A is REAL array, dimension (LDA,N) The m by n matrix A.
LDA
LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M).
S
S is REAL array, dimension (NS) The singular values from the (partial) SVD of B, sorted in decreasing order.
NS
NS is INTEGER The number of singular values/vectors from the (partial) SVD of B.
U
U is REAL array, dimension (LDU,NS) The n by ns orthogonal matrix U in S = U' * B * V.
LDU
LDU is INTEGER The leading dimension of the array U. LDU >= max(1,N)
VT
VT is REAL array, dimension (LDVT,N) The n by ns orthogonal matrix V in S = U' * B * V.
LDVT
LDVT is INTEGER The leading dimension of the array VT.
WORK
WORK is REAL array, dimension (M,N)
RESID
RESID is REAL The test ratio: norm(S - U' * A * V) / ( n * norm(A) * EPS )
- Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 125 of file sbdt05.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page sbdt05(3) is an alias of sbdt05.f(3).
Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK