zlaed0.f(3) LAPACK zlaed0.f(3)
NAME
zlaed0.f -
SYNOPSIS
Functions/Subroutines
subroutine zlaed0 (QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, RWORK, IWORK, INFO)
ZLAED0
Function/Subroutine Documentation
subroutine zlaed0 (integerQSIZ, integerN, double precision, dimension( * )D, double precision, dimension( * )E, complex*16, dimension( ldq, *
)Q, integerLDQ, complex*16, dimension( ldqs, * )QSTORE, integerLDQS, double precision, dimension( * )RWORK, integer, dimension( * )IWORK,
integerINFO)
ZLAED0
Purpose:
Using the divide and conquer method, ZLAED0 computes all eigenvalues
of a symmetric tridiagonal matrix which is one diagonal block of
those from reducing a dense or band Hermitian matrix and
corresponding eigenvectors of the dense or band matrix.
Parameters:
QSIZ
QSIZ is INTEGER
The dimension of the unitary matrix used to reduce
the full matrix to tridiagonal form. QSIZ >= N if ICOMPQ = 1.
N
N is INTEGER
The dimension of the symmetric tridiagonal matrix. N >= 0.
D
D is DOUBLE PRECISION array, dimension (N)
On entry, the diagonal elements of the tridiagonal matrix.
On exit, the eigenvalues in ascending order.
E
E is DOUBLE PRECISION array, dimension (N-1)
On entry, the off-diagonal elements of the tridiagonal matrix.
On exit, E has been destroyed.
Q
Q is COMPLEX*16 array, dimension (LDQ,N)
On entry, Q must contain an QSIZ x N matrix whose columns
unitarily orthonormal. It is a part of the unitary matrix
that reduces the full dense Hermitian matrix to a
(reducible) symmetric tridiagonal matrix.
LDQ
LDQ is INTEGER
The leading dimension of the array Q. LDQ >= max(1,N).
IWORK
IWORK is INTEGER array,
the dimension of IWORK must be at least
6 + 6*N + 5*N*lg N
( lg( N ) = smallest integer k
such that 2^k >= N )
RWORK
RWORK is DOUBLE PRECISION array,
dimension (1 + 3*N + 2*N*lg N + 3*N**2)
( lg( N ) = smallest integer k
such that 2^k >= N )
QSTORE
QSTORE is COMPLEX*16 array, dimension (LDQS, N)
Used to store parts of
the eigenvector matrix when the updating matrix multiplies
take place.
LDQS
LDQS is INTEGER
The leading dimension of the array QSTORE.
LDQS >= max(1,N).
INFO
INFO is INTEGER
= 0: successful exit.
< 0: if INFO = -i, the i-th argument had an illegal value.
> 0: The algorithm failed to compute an eigenvalue while
working on the submatrix lying in rows and columns
INFO/(N+1) through mod(INFO,N+1).
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
Definition at line 145 of file zlaed0.f.
Author
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Version 3.4.1 Sun May 26 2013 zlaed0.f(3)