191 SUBROUTINE cgebd2( M, N, A, LDA, D, E, TAUQ, TAUP, WORK, INFO )
199 INTEGER INFO, LDA, M, N
203 COMPLEX A( lda, * ), TAUP( * ), TAUQ( * ), WORK( * )
210 parameter ( zero = ( 0.0e+0, 0.0e+0 ),
211 $ one = ( 1.0e+0, 0.0e+0 ) )
221 INTRINSIC conjg, max, min
230 ELSE IF( n.LT.0 )
THEN
232 ELSE IF( lda.LT.max( 1, m ) )
THEN
236 CALL xerbla(
'CGEBD2', -info )
249 CALL clarfg( m-i+1, alpha, a( min( i+1, m ), i ), 1,
257 $
CALL clarf(
'Left', m-i+1, n-i, a( i, i ), 1,
258 $ conjg( tauq( i ) ), a( i, i+1 ), lda, work )
266 CALL clacgv( n-i, a( i, i+1 ), lda )
268 CALL clarfg( n-i, alpha, a( i, min( i+2, n ) ),
275 CALL clarf(
'Right', m-i, n-i, a( i, i+1 ), lda,
276 $ taup( i ), a( i+1, i+1 ), lda, work )
277 CALL clacgv( n-i, a( i, i+1 ), lda )
291 CALL clacgv( n-i+1, a( i, i ), lda )
293 CALL clarfg( n-i+1, alpha, a( i, min( i+1, n ) ), lda,
301 $
CALL clarf(
'Right', m-i, n-i+1, a( i, i ), lda,
302 $ taup( i ), a( i+1, i ), lda, work )
303 CALL clacgv( n-i+1, a( i, i ), lda )
312 CALL clarfg( m-i, alpha, a( min( i+2, m ), i ), 1,
319 CALL clarf(
'Left', m-i, n-i, a( i+1, i ), 1,
320 $ conjg( tauq( i ) ), a( i+1, i+1 ), lda,
subroutine clarfg(N, ALPHA, X, INCX, TAU)
CLARFG generates an elementary reflector (Householder matrix).
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine clacgv(N, X, INCX)
CLACGV conjugates a complex vector.
subroutine clarf(SIDE, M, N, V, INCV, TAU, C, LDC, WORK)
CLARF applies an elementary reflector to a general rectangular matrix.
subroutine cgebd2(M, N, A, LDA, D, E, TAUQ, TAUP, WORK, INFO)
CGEBD2 reduces a general matrix to bidiagonal form using an unblocked algorithm.