Scroll to navigation

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/dbdt01.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/dbdt01.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/TESTING/EIG/dbdt01.f

SYNOPSIS

Functions/Subroutines


subroutine DBDT01 (m, n, kd, a, lda, q, ldq, d, e, pt, ldpt, work, resid)
DBDT01

Function/Subroutine Documentation

subroutine DBDT01 (integer m, integer n, integer kd, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldq, * ) q, integer ldq, double precision, dimension( * ) d, double precision, dimension( * ) e, double precision, dimension( ldpt, * ) pt, integer ldpt, double precision, dimension( * ) work, double precision resid)

DBDT01

Purpose:

!>
!> DBDT01 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 DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (min(M,N))
!>          The diagonal elements of the bidiagonal matrix B.
!> 

E

!>          E is DOUBLE PRECISION 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 DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (M+N)
!> 

RESID

!>          RESID is DOUBLE PRECISION
!>          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 dbdt01.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Version 3.12.0 LAPACK