cunmtr(3)

NAME

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

UPLO

          UPLO is CHARACTER*1
          = 'U': Upper triangle of A contains elementary reflectors
                 from CHETRD;
          = 'L': Lower triangle of A contains elementary reflectors
                 from CHETRD.

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.

A

          A is COMPLEX array, dimension
                               (LDA,M) if SIDE = 'L'
                               (LDA,N) if SIDE = 'R'
          The vectors which define the elementary reflectors, as
          returned by CHETRD.

LDA

LDA is INTEGER
The leading dimension of the array A.LDA >= max(1, M) if SIDE = ‘L’;
LDA >= max(1, N) if SIDE = ‘R’.

TAU

          TAU is COMPLEX array, dimension
                               (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

          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 172 of file cunmtr.f.

Author

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