dgemqrt.f man page
subroutine dgemqrt (SIDE, TRANS, M, N, K, NB, V, LDV, T, LDT, C, LDC, WORK, INFO)
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 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'.
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 in CGEQRT.
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
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Definition at line 170 of file dgemqrt.f.
Generated automatically by Doxygen for LAPACK from the source code.
The man page dgemqrt(3) is an alias of dgemqrt.f(3).