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cunmrq-f(3)

cunmrq.f –

Synopsis

Functions/Subroutines

subroutine cunmrq (SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, LWORK, INFO)
CUNMRQ

Function/Subroutine Documentation

subroutine cunmrq (characterSIDE, characterTRANS, integerM, integerN, integerK, complex, dimension( lda, * )A, integerLDA, complex, dimension( * )TAU, complex, dimension( ldc, * )C, integerLDC, complex, dimension( * )WORK, integerLWORK, integerINFO)

CUNMRQ

Purpose:

 CUNMRQ 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 defined as the product of k
 elementary reflectors
 Q = H(1)**H H(2)**H . . . H(k)**H
 as returned by CGERQF. Q is of order M if SIDE = 'L' and of order N
 if SIDE = 'R'.

 

Parameters:

SIDE

 SIDE is CHARACTER*1
 = 'L': apply Q or Q**H from the Left;
 = 'R': apply Q or Q**H from the Right.

TRANS

 TRANS is CHARACTER*1
 = 'N': No transpose, apply Q;
 = 'C': Transpose, apply Q**H.

M

 M is INTEGER
 The number of rows of the matrix C. M >= 0.

N

 N is INTEGER
 The number of columns of the matrix C. N >= 0.

K

 K is INTEGER
 The number of elementary reflectors whose product defines
 the matrix Q.
 If SIDE = 'L', M >= K >= 0;
 if SIDE = 'R', N >= K >= 0.

A

 A is COMPLEX array, dimension
 (LDA,M) if SIDE = 'L',
 (LDA,N) if SIDE = 'R'
 The i-th row must contain the vector which defines the
 elementary reflector H(i), for i = 1,2,...,k, as returned by
 CGERQF in the last k rows of its array argument A.

LDA

 LDA is INTEGER
 The leading dimension of the array A. LDA >= max(1,K).

TAU

 TAU is COMPLEX array, dimension (K)
 TAU(i) must contain the scalar factor of the elementary
 reflector H(i), as returned by CGERQF.

C

 C is COMPLEX array, dimension (LDC,N)
 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

 LDC is INTEGER
 The leading dimension of the array C. LDC >= max(1,M).

WORK

 WORK is COMPLEX array, dimension (MAX(1,LWORK))
 On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

LWORK

 LWORK is INTEGER
 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

 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 170 of file cunmrq.f.

Author

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