137 SUBROUTINE cgeqrfp( M, N, A, LDA, TAU, WORK, LWORK, INFO )
145 INTEGER info, lda, lwork, m, n
148 COMPLEX a( lda, * ), tau( * ), work( * )
155 INTEGER i, ib, iinfo, iws, k, ldwork, lwkopt, nb,
173 nb =
ilaenv( 1,
'CGEQRF',
' ', m, n, -1, -1 )
176 lquery = ( lwork.EQ.-1 )
179 ELSE IF( n.LT.0 )
THEN
181 ELSE IF( lda.LT.max( 1, m ) )
THEN
183 ELSE IF( lwork.LT.max( 1, n ) .AND. .NOT.lquery )
THEN
187 CALL
xerbla(
'CGEQRFP', -info )
189 ELSE IF( lquery )
THEN
204 IF( nb.GT.1 .AND. nb.LT.k )
THEN
208 nx = max( 0,
ilaenv( 3,
'CGEQRF',
' ', m, n, -1, -1 ) )
215 IF( lwork.LT.iws )
THEN
221 nbmin = max( 2,
ilaenv( 2,
'CGEQRF',
' ', m, n, -1,
227 IF( nb.GE.nbmin .AND. nb.LT.k .AND. nx.LT.k )
THEN
231 DO 10 i = 1, k - nx, nb
232 ib = min( k-i+1, nb )
237 CALL
cgeqr2p( m-i+1, ib, a( i, i ), lda, tau( i ), work,
244 CALL
clarft(
'Forward',
'Columnwise', m-i+1, ib,
245 $ a( i, i ), lda, tau( i ), work, ldwork )
249 CALL
clarfb(
'Left',
'Conjugate transpose',
'Forward',
250 $
'Columnwise', m-i+1, n-i-ib+1, ib,
251 $ a( i, i ), lda, work, ldwork, a( i, i+ib ),
252 $ lda, work( ib+1 ), ldwork )
262 $ CALL
cgeqr2p( m-i+1, n-i+1, a( i, i ), lda, tau( i ), work,
subroutine clarfb(SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV, T, LDT, C, LDC, WORK, LDWORK)
CLARFB applies a block reflector or its conjugate-transpose to a general rectangular matrix...
subroutine cgeqr2p(M, N, A, LDA, TAU, WORK, INFO)
CGEQR2P computes the QR factorization of a general rectangular matrix with non-negative diagonal elem...
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine clarft(DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT)
CLARFT forms the triangular factor T of a block reflector H = I - vtvH
INTEGER function ilaenv(ISPEC, NAME, OPTS, N1, N2, N3, N4)
subroutine cgeqrfp(M, N, A, LDA, TAU, WORK, LWORK, INFO)
CGEQRFP