cbdt01.f - Man Page

TESTING/EIG/cbdt01.f

Synopsis

Functions/Subroutines

subroutine cbdt01 (m, n, kd, a, lda, q, ldq, d, e, pt, ldpt, work, rwork, resid)
CBDT01

Function/Subroutine Documentation

subroutine cbdt01 (integer m, integer n, integer kd, complex, dimension( lda, * ) a, integer lda, complex, dimension( ldq, * ) q, integer ldq, real, dimension( * ) d, real, dimension( * ) e, complex, dimension( ldpt, * ) pt, integer ldpt, complex, dimension( * ) work, real, dimension( * ) rwork, real resid)

CBDT01

Purpose:

 CBDT01 reconstructs a general matrix A from its bidiagonal form
    A = Q * B * P**H
 where Q (m by min(m,n)) and P**H (min(m,n) by n) are unitary
 matrices and B is bidiagonal.

 The test ratio to test the reduction is
    RESID = norm(A - Q * B * P**H) / ( n * norm(A) * EPS )
 where EPS is the machine precision.
Parameters

M

          M is INTEGER
          The number of rows of the matrices A and Q.

N

          N is INTEGER
          The number of columns of the matrices A and P**H.

KD

          KD is INTEGER
          If KD = 0, B is diagonal and the array E is not referenced.
          If KD = 1, the reduction was performed by xGEBRD; B is upper
          bidiagonal if M >= N, and lower bidiagonal if M < N.
          If KD = -1, the reduction was performed by xGBBRD; B is
          always upper bidiagonal.

A

          A is COMPLEX 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).

Q

          Q is COMPLEX array, dimension (LDQ,N)
          The m by min(m,n) unitary matrix Q in the reduction
          A = Q * B * P**H.

LDQ

          LDQ is INTEGER
          The leading dimension of the array Q.  LDQ >= max(1,M).

D

          D is REAL array, dimension (min(M,N))
          The diagonal elements of the bidiagonal matrix B.

E

          E is REAL array, dimension (min(M,N)-1)
          The superdiagonal elements of the bidiagonal matrix B if
          m >= n, or the subdiagonal elements of B if m < n.

PT

          PT is COMPLEX array, dimension (LDPT,N)
          The min(m,n) by n unitary matrix P**H in the reduction
          A = Q * B * P**H.

LDPT

          LDPT is INTEGER
          The leading dimension of the array PT.
          LDPT >= max(1,min(M,N)).

WORK

          WORK is COMPLEX array, dimension (M+N)

RWORK

          RWORK is REAL array, dimension (M)

RESID

          RESID is REAL
          The test ratio:
          norm(A - Q * B * P**H) / ( n * norm(A) * EPS )
Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 145 of file cbdt01.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page cbdt01(3) is an alias of cbdt01.f(3).

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