dorm2l (l)  Linux Manuals
dorm2l: overwrites the general real m by n matrix C with Q * C if SIDE = aqLaq and TRANS = aqNaq, or Qaq* C if SIDE = aqLaq and TRANS = aqTaq, or C * Q if SIDE = aqRaq and TRANS = aqNaq, or C * Qaq if SIDE = aqRaq and TRANS = aqTaq,
NAME
DORM2L  overwrites the general real m by n matrix C with Q * C if SIDE = aqLaq and TRANS = aqNaq, or Qaq* C if SIDE = aqLaq and TRANS = aqTaq, or C * Q if SIDE = aqRaq and TRANS = aqNaq, or C * Qaq if SIDE = aqRaq and TRANS = aqTaq,SYNOPSIS
 SUBROUTINE DORM2L(
 SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, INFO )
 CHARACTER SIDE, TRANS
 INTEGER INFO, K, LDA, LDC, M, N
 DOUBLE PRECISION A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
PURPOSE
DORM2L overwrites the general real m by n matrix C with where Q is a real orthogonal matrix defined as the product of k elementary reflectorsQ
as returned by DGEQLF. Q is of order m if SIDE = aqLaq and of order n if SIDE = aqRaq.
ARGUMENTS
 SIDE (input) CHARACTER*1

= aqLaq: apply Q or Qaq from the Left
= aqRaq: apply Q or Qaq from the Right  TRANS (input) CHARACTER*1

= aqNaq: apply Q (No transpose)
= aqTaq: apply Qaq (Transpose)  M (input) INTEGER
 The number of rows of the matrix C. M >= 0.
 N (input) INTEGER
 The number of columns of the matrix C. N >= 0.
 K (input) INTEGER
 The number of elementary reflectors whose product defines the matrix Q. If SIDE = aqLaq, M >= K >= 0; if SIDE = aqRaq, N >= K >= 0.
 A (input) DOUBLE PRECISION array, dimension (LDA,K)
 The ith column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by DGEQLF in the last k columns of its array argument A. A is modified by the routine but restored on exit.
 LDA (input) INTEGER
 The leading dimension of the array A. If SIDE = aqLaq, LDA >= max(1,M); if SIDE = aqRaq, LDA >= max(1,N).
 TAU (input) DOUBLE PRECISION array, dimension (K)
 TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DGEQLF.
 C (input/output) DOUBLE PRECISION array, dimension (LDC,N)
 On entry, the m by n matrix C. On exit, C is overwritten by Q*C or Qaq*C or C*Qaq or C*Q.
 LDC (input) INTEGER
 The leading dimension of the array C. LDC >= max(1,M).
 WORK (workspace) DOUBLE PRECISION array, dimension
 (N) if SIDE = aqLaq, (M) if SIDE = aqRaq
 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value