SRC/sgemqrt.f(3) Library Functions Manual SRC/sgemqrt.f(3) NAME SRC/sgemqrt.f SYNOPSIS Functions/Subroutines subroutine sgemqrt (side, trans, m, n, k, nb, v, ldv, t, ldt, c, ldc, work, info) SGEMQRT Function/Subroutine Documentation subroutine sgemqrt (character side, character trans, integer m, integer n, integer k, integer nb, real, dimension( ldv, * ) v, integer ldv, real, dimension( ldt, * ) t, integer ldt, real, dimension( ldc, * ) c, integer ldc, real, dimension( * ) work, integer info) SGEMQRT Purpose: !> !> SGEMQRT 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 SGEQRT. !> !> 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; !> = '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. !> 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 SGEQRT. !> V !> V is REAL 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 !> SGEQRT 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 REAL array, dimension (LDT,K) !> The upper triangular factors of the block reflectors !> as returned by SGEQRT, stored as a NB-by-N matrix. !> LDT !> LDT is INTEGER !> The leading dimension of the array T. LDT >= NB. !> C !> C is REAL 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 REAL 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 sgemqrt.f. Author Generated automatically by Doxygen for LAPACK from the source code. LAPACK Version 3.12.0 SRC/sgemqrt.f(3)