122 SUBROUTINE zgeqr2( M, N, A, LDA, TAU, WORK, INFO )
130 INTEGER info, lda, m, n
133 COMPLEX*16 a( lda, * ), tau( * ), work( * )
140 parameter( one = ( 1.0d+0, 0.0d+0 ) )
150 INTRINSIC dconjg, max, min
159 ELSE IF( n.LT.0 )
THEN
161 ELSE IF( lda.LT.max( 1, m ) )
THEN
165 CALL
xerbla(
'ZGEQR2', -info )
175 CALL
zlarfg( m-i+1, a( i, i ), a( min( i+1, m ), i ), 1,
183 CALL
zlarf(
'Left', m-i+1, n-i, a( i, i ), 1,
184 $ dconjg( tau( i ) ), a( i, i+1 ), lda, work )
subroutine zgeqr2(M, N, A, LDA, TAU, WORK, INFO)
ZGEQR2 computes the QR factorization of a general rectangular matrix using an unblocked algorithm...
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 zlarfg(N, ALPHA, X, INCX, TAU)
ZLARFG generates an elementary reflector (Householder matrix).