128 SUBROUTINE sgelq2( M, N, A, LDA, TAU, WORK, INFO )
135 INTEGER INFO, LDA, M, N
138 REAL A( LDA, * ), TAU( * ), WORK( * )
145 parameter( one = 1.0e+0 )
164 ELSE IF( n.LT.0 )
THEN
166 ELSE IF( lda.LT.max( 1, m ) )
THEN
170 CALL xerbla(
'SGELQ2', -info )
180 CALL slarfg( n-i+1, a( i, i ), a( i, min( i+1, n ) ), lda,
188 CALL slarf(
'Right', m-i, n-i+1, a( i, i ), lda, tau( i ),
189 $ a( i+1, i ), lda, work )
subroutine xerbla(srname, info)
subroutine sgelq2(m, n, a, lda, tau, work, info)
SGELQ2 computes the LQ factorization of a general rectangular matrix using an unblocked algorithm.
subroutine slarf(side, m, n, v, incv, tau, c, ldc, work)
SLARF applies an elementary reflector to a general rectangular matrix.
subroutine slarfg(n, alpha, x, incx, tau)
SLARFG generates an elementary reflector (Householder matrix).