CUNMTR (3) Linux Manual Page
cunmtr.f –
Synopsis
Functions/Subroutines
subroutine cunmtr (SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C, LDC, WORK, LWORK, INFO)CUNMTR
Function/Subroutine Documentation
subroutine cunmtr (characterSIDE, characterUPLO, characterTRANS, integerM, integerN, complex, dimension( lda, * )A, integerLDA, complex, dimension( * )TAU, complex, dimension( ldc, * )C, integerLDC, complex, dimension( * )WORK, integerLWORK, integerINFO)
CUNMTR Purpose:
CUNMTR overwrites the general complex M-by-N matrix C with
SIDE = ‘L’ SIDE = ‘R’
TRANS = ‘N’: Q * C C * Q
TRANS = ‘C’: Q**H * C C * Q**H
where Q is a complex unitary matrix of order nq, with nq = m if
SIDE = ‘L’ and nq = n if SIDE = ‘R’. Q is defined as the product of
nq-1 elementary reflectors, as returned by CHETRD:
if UPLO = ‘U’, Q = H(nq-1) . . . H(2) H(1);
if UPLO = ‘L’, Q = H(1) H(2) . . . H(nq-1).
Parameters:
- SIDE
SIDE is CHARACTER*1
UPLO
= ‘L’: apply Q or Q**H from the Left;
= ‘R’: apply Q or Q**H from the Right.UPLO is CHARACTER*1
TRANS
= ‘U’: Upper triangle of A contains elementary reflectors
from CHETRD;
= ‘L’: Lower triangle of A contains elementary reflectors
from CHETRD.TRANS is CHARACTER*1
M
= ‘N’: No transpose, apply Q;
= ‘C’: Conjugate transpose, apply Q**H.M is INTEGER
N
The number of rows of the matrix C. M >= 0.N is INTEGER
A
The number of columns of the matrix C. N >= 0.A is COMPLEX array, dimension
LDA
(LDA,M) if SIDE = ‘L’
(LDA,N) if SIDE = ‘R’
The vectors which define the elementary reflectors, as
returned by CHETRD.LDA is INTEGER
TAU
The leading dimension of the array A.
LDA >= max(1,M) if SIDE = ‘L’; LDA >= max(1,N) if SIDE = ‘R’.TAU is COMPLEX array, dimension
C
(M-1) if SIDE = ‘L’
(N-1) if SIDE = ‘R’
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by CHETRD.C is COMPLEX array, dimension (LDC,N)
LDC
On entry, the M-by-N matrix C.
On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.LDC is INTEGER
WORK
The leading dimension of the array C. LDC >= max(1,M).WORK is COMPLEX array, dimension (MAX(1,LWORK))
LWORK
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.LWORK is INTEGER
INFO
The dimension of the array WORK.
If SIDE = ‘L’, LWORK >= max(1,N);
if SIDE = ‘R’, LWORK >= max(1,M).
For optimum performance LWORK >= N*NB if SIDE = ‘L’, and
LWORK >=M*NB if SIDE = ‘R’, where NB is the optimal
blocksize.
If LWORK = -1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
Author:
- Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
- November 2011
Definition at line 172 of file cunmtr.f.