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cunmtr-f(3)

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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