zbdt05.f - Man Page

TESTING/EIG/zbdt05.f

Synopsis

Functions/Subroutines

subroutine zbdt05 (m, n, a, lda, s, ns, u, ldu, vt, ldvt, work, resid)
ZBDT05

Function/Subroutine Documentation

subroutine zbdt05 (integer m, integer n, complex*16, dimension( lda, * ) a, integer lda, double precision, dimension( * ) s, integer ns, complex*16, dimension( * ) u, integer ldu, complex*16, dimension( ldvt, * ) vt, integer ldvt, complex*16, dimension( * ) work, double precision resid)

ZBDT05

Purpose:

 ZBDT05 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 COMPLEX*16 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 DOUBLE PRECISION 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 COMPLEX*16 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 COMPLEX*16 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 COMPLEX*16 array, dimension (M,N)

RESID

          RESID is DOUBLE PRECISION
          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 123 of file zbdt05.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page zbdt05(3) is an alias of zbdt05.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK