190 SUBROUTINE sgebd2( M, N, A, LDA, D, E, TAUQ, TAUP, WORK, INFO )
198 INTEGER INFO, LDA, M, N
201 REAL A( lda, * ), D( * ), E( * ), TAUP( * ),
202 $ tauq( * ), work( * )
209 parameter ( zero = 0.0e+0, one = 1.0e+0 )
227 ELSE IF( n.LT.0 )
THEN
229 ELSE IF( lda.LT.max( 1, m ) )
THEN
233 CALL xerbla(
'SGEBD2', -info )
245 CALL slarfg( m-i+1, a( i, i ), a( min( i+1, m ), i ), 1,
253 $
CALL slarf(
'Left', m-i+1, n-i, a( i, i ), 1, tauq( i ),
254 $ a( i, i+1 ), lda, work )
262 CALL slarfg( n-i, a( i, i+1 ), a( i, min( i+2, n ) ),
269 CALL slarf(
'Right', m-i, n-i, a( i, i+1 ), lda,
270 $ taup( i ), a( i+1, i+1 ), lda, work )
284 CALL slarfg( n-i+1, a( i, i ), a( i, min( i+1, n ) ), lda,
292 $
CALL slarf(
'Right', m-i, n-i+1, a( i, i ), lda,
293 $ taup( i ), a( i+1, i ), lda, work )
301 CALL slarfg( m-i, a( i+1, i ), a( min( i+2, m ), i ), 1,
308 CALL slarf(
'Left', m-i, n-i, a( i+1, i ), 1, tauq( i ),
309 $ a( i+1, i+1 ), lda, work )
subroutine slarfg(N, ALPHA, X, INCX, TAU)
SLARFG generates an elementary reflector (Householder matrix).
subroutine sgebd2(M, N, A, LDA, D, E, TAUQ, TAUP, WORK, INFO)
SGEBD2 reduces a general matrix to bidiagonal form using an unblocked algorithm.
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine slarf(SIDE, M, N, V, INCV, TAU, C, LDC, WORK)
SLARF applies an elementary reflector to a general rectangular matrix.