table of contents
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/sormtr.f(3) | Library Functions Manual | /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/sormtr.f(3) |
NAME¶
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/sormtr.f
SYNOPSIS¶
Functions/Subroutines¶
subroutine SORMTR (side, uplo, trans, m, n, a, lda, tau, c,
ldc, work, lwork, info)
SORMTR
Function/Subroutine Documentation¶
subroutine SORMTR (character side, character uplo, character trans, integer m, integer n, real, dimension( lda, * ) a, integer lda, real, dimension( * ) tau, real, dimension( ldc, * ) c, integer ldc, real, dimension( * ) work, integer lwork, integer info)¶
SORMTR
Purpose:
!> !> SORMTR overwrites the general real M-by-N matrix C with !> !> SIDE = 'L' SIDE = 'R' !> TRANS = 'N': Q * C C * Q !> TRANS = 'T': Q**T * C C * Q**T !> !> where Q is a real orthogonal 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 SSYTRD: !> !> 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**T from the Left; !> = 'R': apply Q or Q**T from the Right. !>
UPLO
!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A contains elementary reflectors !> from SSYTRD; !> = 'L': Lower triangle of A contains elementary reflectors !> from SSYTRD. !>
TRANS
!> TRANS is CHARACTER*1 !> = 'N': No transpose, apply Q; !> = 'T': Transpose, apply Q**T. !>
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 REAL array, dimension !> (LDA,M) if SIDE = 'L' !> (LDA,N) if SIDE = 'R' !> The vectors which define the elementary reflectors, as !> returned by SSYTRD. !>
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 REAL 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 SSYTRD. !>
C
!> C is REAL array, dimension (LDC,N) !> On entry, the M-by-N matrix C. !> On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q. !>
LDC
!> LDC is INTEGER !> The leading dimension of the array C. LDC >= max(1,M). !>
WORK
!> WORK is REAL 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.
Definition at line 170 of file sormtr.f.
Author¶
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