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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dopmtr.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dopmtr.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dopmtr.f

SYNOPSIS

Functions/Subroutines


subroutine DOPMTR (side, uplo, trans, m, n, ap, tau, c, ldc, work, info)
DOPMTR

Function/Subroutine Documentation

subroutine DOPMTR (character side, character uplo, character trans, integer m, integer n, double precision, dimension( * ) ap, double precision, dimension( * ) tau, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( * ) work, integer info)

DOPMTR

Purpose:

!>
!> DOPMTR 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 DSPTRD 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

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 triangular packed storage used in previous
!>                 call to DSPTRD;
!>          = 'L': Lower triangular packed storage used in previous
!>                 call to DSPTRD.
!> 

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.
!> 

AP

!>          AP is DOUBLE PRECISION 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 DSPTRD.  AP is modified by the routine but
!>          restored on exit.
!> 

TAU

!>          TAU is DOUBLE PRECISION 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 DSPTRD.
!> 

C

!>          C is DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension
!>                                   (N) if SIDE = 'L'
!>                                   (M) if SIDE = 'R'
!> 

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 148 of file dopmtr.f.

Author

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Version 3.12.0 LAPACK