123 SUBROUTINE sgelqt( M, N, MB, A, LDA, T, LDT, WORK, INFO )
131 INTEGER INFO, LDA, LDT, M, N, MB
134 REAL A( lda, * ), T( ldt, * ), WORK( * )
141 INTEGER I, IB, IINFO, K
153 ELSE IF( n.LT.0 )
THEN
155 ELSE IF( mb.LT.1 .OR. ( mb.GT.min(m,n) .AND. min(m,n).GT.0 ) )
THEN
157 ELSE IF( lda.LT.max( 1, m ) )
THEN
159 ELSE IF( ldt.LT.mb )
THEN
163 CALL xerbla(
'SGELQT', -info )
175 ib = min( k-i+1, mb )
179 CALL sgelqt3( ib, n-i+1, a(i,i), lda, t(1,i), ldt, iinfo )
184 CALL slarfb(
'R',
'N',
'F',
'R', m-i-ib+1, n-i+1, ib,
185 $ a( i, i ), lda, t( 1, i ), ldt,
186 $ a( i+ib, i ), lda, work , m-i-ib+1 )
subroutine sgeqrt2(M, N, A, LDA, T, LDT, INFO)
SGEQRT2 computes a QR factorization of a general real or complex matrix using the compact WY represen...
subroutine sgelqt(M, N, MB, A, LDA, T, LDT, WORK, INFO)
recursive subroutine sgelqt3(M, N, A, LDA, T, LDT, INFO)
subroutine xerbla(SRNAME, INFO)
XERBLA
recursive subroutine sgeqrt3(M, N, A, LDA, T, LDT, INFO)
SGEQRT3 recursively computes a QR factorization of a general real or complex matrix using the compact...
subroutine slarfb(SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV, T, LDT, C, LDC, WORK, LDWORK)
SLARFB applies a block reflector or its transpose to a general rectangular matrix.