TESTING/EIG/zbdt01.f(3) | Library Functions Manual | TESTING/EIG/zbdt01.f(3) |
NAME
TESTING/EIG/zbdt01.f
SYNOPSIS
Functions/Subroutines
subroutine zbdt01 (m, n, kd, a, lda, q, ldq, d, e, pt,
ldpt, work, rwork, resid)
ZBDT01
Function/Subroutine Documentation
subroutine zbdt01 (integer m, integer n, integer kd, complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( ldq, * ) q, integer ldq, double precision, dimension( * ) d, double precision, dimension( * ) e, complex*16, dimension( ldpt, * ) pt, integer ldpt, complex*16, dimension( * ) work, double precision, dimension( * ) rwork, double precision resid)
ZBDT01
Purpose:
ZBDT01 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*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).
Q
Q is COMPLEX*16 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 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 COMPLEX*16 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*16 array, dimension (M+N)
RWORK
RWORK is DOUBLE PRECISION array, dimension (M)
RESID
RESID is DOUBLE PRECISION 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 zbdt01.f.
Author
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