Scroll to navigation

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/sbdt01.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/sbdt01.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/sbdt01.f

SYNOPSIS

Functions/Subroutines


subroutine SBDT01 (m, n, kd, a, lda, q, ldq, d, e, pt, ldpt, work, resid)
SBDT01

Function/Subroutine Documentation

subroutine SBDT01 (integer m, integer n, integer kd, real, dimension( lda, * ) a, integer lda, real, dimension( ldq, * ) q, integer ldq, real, dimension( * ) d, real, dimension( * ) e, real, dimension( ldpt, * ) pt, integer ldpt, real, dimension( * ) work, real resid)

SBDT01

Purpose:

!>
!> SBDT01 reconstructs a general matrix A from its bidiagonal form
!>    A = Q * B * P**T
!> where Q (m by min(m,n)) and P**T (min(m,n) by n) are orthogonal
!> matrices and B is bidiagonal.
!>
!> The test ratio to test the reduction is
!>    RESID = norm(A - Q * B * P**T) / ( 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**T.
!> 

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 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).
!> 

Q

!>          Q is REAL array, dimension (LDQ,N)
!>          The m by min(m,n) orthogonal matrix Q in the reduction
!>          A = Q * B * P**T.
!> 

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 REAL array, dimension (LDPT,N)
!>          The min(m,n) by n orthogonal matrix P**T in the reduction
!>          A = Q * B * P**T.
!> 

LDPT

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

WORK

!>          WORK is REAL array, dimension (M+N)
!> 

RESID

!>          RESID is REAL
!>          The test ratio:
!>          norm(A - Q * B * P**T) / ( n * norm(A) * EPS )
!> 

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 139 of file sbdt01.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Version 3.12.0 LAPACK