cunmrz(3)

NAME

cunmrz.f –

SYNOPSIS

Functions/Subroutines

subroutine cunmrz (SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, WORK, LWORK, INFO)
CUNMRZ

Function/Subroutine Documentation

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

CUNMRZ

Purpose:

 CUNMRZ 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(2) . . . H(k)
 as returned by CTZRZF. 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':  Conjugate 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.

L

          L is INTEGER
          The number of columns of the matrix A containing
          the meaningful part of the Householder reflectors.
          If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 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
          CTZRZF in the last k rows of its array argument A.
          A is modified by the routine but restored on exit.

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 CTZRZF.

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

Contributors:

A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA

Further Details:

Definition at line 189 of file cunmrz.f.

Author

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