LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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◆ cupmtr()

subroutine cupmtr ( character side,
character uplo,
character trans,
integer m,
integer n,
complex, dimension( * ) ap,
complex, dimension( * ) tau,
complex, dimension( ldc, * ) c,
integer ldc,
complex, dimension( * ) work,
integer info )

CUPMTR

Download CUPMTR + dependencies [TGZ] [ZIP] [TXT]

Purpose:
!>
!> CUPMTR 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 CHPTRD using packed
!> storage:
!>
!> if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);
!>
!> if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).
!> 
Parameters
[in]SIDE
!>          SIDE is CHARACTER*1
!>          = 'L': apply Q or Q**H from the Left;
!>          = 'R': apply Q or Q**H from the Right.
!> 
[in]UPLO
!>          UPLO is CHARACTER*1
!>          = 'U': Upper triangular packed storage used in previous
!>                 call to CHPTRD;
!>          = 'L': Lower triangular packed storage used in previous
!>                 call to CHPTRD.
!> 
[in]TRANS
!>          TRANS is CHARACTER*1
!>          = 'N':  No transpose, apply Q;
!>          = 'C':  Conjugate transpose, apply Q**H.
!> 
[in]M
!>          M is INTEGER
!>          The number of rows of the matrix C. M >= 0.
!> 
[in]N
!>          N is INTEGER
!>          The number of columns of the matrix C. N >= 0.
!> 
[in]AP
!>          AP is COMPLEX array, dimension
!>                               (M*(M+1)/2) if SIDE = 'L'
!>                               (N*(N+1)/2) if SIDE = 'R'
!>          The vectors which define the elementary reflectors, as
!>          returned by CHPTRD.  AP is modified by the routine but
!>          restored on exit.
!> 
[in]TAU
!>          TAU is COMPLEX array, dimension (M-1) if SIDE = 'L'
!>                                     or (N-1) if SIDE = 'R'
!>          TAU(i) must contain the scalar factor of the elementary
!>          reflector H(i), as returned by CHPTRD.
!> 
[in,out]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.
!> 
[in]LDC
!>          LDC is INTEGER
!>          The leading dimension of the array C. LDC >= max(1,M).
!> 
[out]WORK
!>          WORK is COMPLEX array, dimension
!>                                   (N) if SIDE = 'L'
!>                                   (M) if SIDE = 'R'
!> 
[out]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.