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SRC/zgemlqt.f(3) LAPACK SRC/zgemlqt.f(3)

SRC/zgemlqt.f


subroutine zgemlqt (side, trans, m, n, k, mb, v, ldv, t, ldt, c, ldc, work, info)
ZGEMLQT

ZGEMLQT

Purpose:


ZGEMLQT 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 defined as the product of K
elementary reflectors:
Q = H(1) H(2) . . . H(K) = I - V T V**H
generated using the compact WY representation as returned by ZGELQT.
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**H from the Left;
= 'R': apply Q or Q**H from the Right.

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.

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.

MB


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

V


V is COMPLEX*16 array, dimension
(LDV,M) if SIDE = 'L',
(LDV,N) if SIDE = 'R'
The i-th row must contain the vector which defines the
elementary reflector H(i), for i = 1,2,...,k, as returned by
ZGELQT in the first K rows of its array argument A.

LDV


LDV is INTEGER
The leading dimension of the array V. LDV >= max(1,K).

T


T is COMPLEX*16 array, dimension (LDT,K)
The upper triangular factors of the block reflectors
as returned by ZGELQT, stored as a MB-by-K matrix.

LDT


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

C


C is COMPLEX*16 array, dimension (LDC,N)
On entry, the M-by-N matrix C.
On exit, C is overwritten by Q C, Q**H C, 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*16 array. The dimension of
WORK is N*MB if SIDE = 'L', or M*MB 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 zgemlqt.f.

Generated automatically by Doxygen for LAPACK from the source code.

Sun Jan 12 2025 15:13:32 Version 3.12.1

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