124 SUBROUTINE zgerq2( M, N, A, LDA, TAU, WORK, INFO )
132 INTEGER INFO, LDA, M, N
135 COMPLEX*16 A( lda, * ), TAU( * ), WORK( * )
142 parameter( one = ( 1.0d+0, 0.0d+0 ) )
161 ELSE IF( n.LT.0 )
THEN
163 ELSE IF( lda.LT.max( 1, m ) )
THEN
167 CALL
xerbla(
'ZGERQ2', -info )
178 CALL
zlacgv( n-k+i, a( m-k+i, 1 ), lda )
179 alpha = a( m-k+i, n-k+i )
180 CALL
zlarfg( n-k+i, alpha, a( m-k+i, 1 ), lda, tau( i ) )
184 a( m-k+i, n-k+i ) = one
185 CALL
zlarf(
'Right', m-k+i-1, n-k+i, a( m-k+i, 1 ), lda,
186 $ tau( i ), a, lda, work )
187 a( m-k+i, n-k+i ) = alpha
188 CALL
zlacgv( n-k+i-1, a( m-k+i, 1 ), lda )
subroutine zlarf(SIDE, M, N, V, INCV, TAU, C, LDC, WORK)
ZLARF applies an elementary reflector to a general rectangular matrix.
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine zlacgv(N, X, INCX)
ZLACGV conjugates a complex vector.
subroutine zgerq2(M, N, A, LDA, TAU, WORK, INFO)
ZGERQ2 computes the RQ factorization of a general rectangular matrix using an unblocked algorithm...
subroutine zlarfg(N, ALPHA, X, INCX, TAU)
ZLARFG generates an elementary reflector (Householder matrix).