dgemqrt.f(3) LAPACK dgemqrt.f(3)
subroutine dgemqrt (SIDE, TRANS, M, N, K, NB, V, LDV, T, LDT, C, LDC, WORK, INFO)
subroutine dgemqrt (characterSIDE, characterTRANS, integerM, integerN, integerK, integerNB,
double precision, dimension( ldv, * )V, integerLDV, double precision, dimension( ldt, *
)T, integerLDT, double precision, dimension( ldc, * )C, integerLDC, double precision,
dimension( * )WORK, integerINFO)
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
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'.
SIDE is CHARACTER*1
= 'L': apply Q or Q**T from the Left;
= 'R': apply Q or Q**T from the Right.
TRANS is CHARACTER*1
= 'N': No transpose, apply Q;
= 'C': Transpose, apply Q**T.
M is INTEGER
The number of rows of the matrix C. M >= 0.
N is INTEGER
The number of columns of the matrix C. N >= 0.
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 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
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
CGEQRT in the first K columns of its array argument A.
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 is DOUBLE PRECISION array, dimension (LDT,K)
The upper triangular factors of the block reflectors
as returned by CGEQRT, stored as a NB-by-N matrix.
LDT is INTEGER
The leading dimension of the array T. LDT >= NB.
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 is INTEGER
The leading dimension of the array C. LDC >= max(1,M).
WORK is DOUBLE PRECISION array. The dimension of
WORK is N*NB if SIDE = 'L', or M*NB if SIDE = 'R'.
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
Definition at line 168 of file dgemqrt.f.
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 dgemqrt.f(3)