SRC/dgemqrt.f(3)           Library Functions Manual           SRC/dgemqrt.f(3)

NAME
       SRC/dgemqrt.f

SYNOPSIS
   Functions/Subroutines
       subroutine dgemqrt (side, trans, m, n, k, nb, v, ldv, t, ldt, c, ldc,
           work, info)
           DGEMQRT

Function/Subroutine Documentation
   subroutine dgemqrt (character side, character trans, integer m, integer n,
       integer k, integer nb, double precision, dimension( ldv, * ) v, integer
       ldv, double precision, dimension( ldt, * ) t, integer ldt, double
       precision, dimension( ldc, * ) c, integer ldc, double precision,
       dimension( * ) work, integer info)
       DGEMQRT

       Purpose:


            DGEMQRT 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 defined as the product of K
            elementary reflectors:

                  Q = H(1) H(2) . . . H(K) = I - V T V**T

            generated using the compact WY representation as returned by DGEQRT.

            Q is of order M if SIDE = 'L' and of order N  if SIDE = 'R'.

       Parameters
           SIDE

                     SIDE is CHARACTER*1
                     = 'L': apply Q or Q**T from the Left;
                     = 'R': apply Q or Q**T from the Right.

           TRANS

                     TRANS is CHARACTER*1
                     = 'N':  No transpose, apply Q;
                     = 'C':  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.

           K

                     K is INTEGER
                     The number of elementary reflectors whose product defines
                     the matrix Q.
                     If SIDE = 'L', M >= K >= 0;
                     if SIDE = 'R', N >= K >= 0.

           NB

                     NB is INTEGER
                     The block size used for the storage of T.  K >= NB >= 1.
                     This must be the same value of NB used to generate T
                     in DGEQRT.

           V

                     V is DOUBLE PRECISION array, dimension (LDV,K)
                     The i-th column must contain the vector which defines the
                     elementary reflector H(i), for i = 1,2,...,k, as returned by
                     DGEQRT in the first K columns of its array argument A.

           LDV

                     LDV is INTEGER
                     The leading dimension of the array V.
                     If SIDE = 'L', LDA >= max(1,M);
                     if SIDE = 'R', LDA >= max(1,N).

           T

                     T is DOUBLE PRECISION array, dimension (LDT,K)
                     The upper triangular factors of the block reflectors
                     as returned by DGEQRT, stored as a NB-by-N matrix.

           LDT

                     LDT is INTEGER
                     The leading dimension of the array T.  LDT >= NB.

           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, Q**T C, 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. The dimension of
                     WORK is N*NB if SIDE = 'L', or  M*NB 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 166 of file dgemqrt.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                SRC/dgemqrt.f(3)