184 SUBROUTINE slarzt( DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT )
191 CHARACTER DIRECT, STOREV
192 INTEGER K, LDT, LDV, N
195 REAL T( LDT, * ), TAU( * ), V( LDV, * )
202 parameter( zero = 0.0e+0 )
219 IF( .NOT.lsame( direct,
'B' ) )
THEN
221 ELSE IF( .NOT.lsame( storev,
'R' ) )
THEN
225 CALL xerbla(
'SLARZT', -info )
230 IF( tau( i ).EQ.zero )
THEN
245 CALL sgemv(
'No transpose', k-i, n, -tau( i ),
246 $ v( i+1, 1 ), ldv, v( i, 1 ), ldv, zero,
251 CALL strmv(
'Lower',
'No transpose',
'Non-unit', k-i,
252 $ t( i+1, i+1 ), ldt, t( i+1, i ), 1 )
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine slarzt(DIRECT, STOREV, N, K, V, LDV, TAU, T, LDT)
SLARZT forms the triangular factor T of a block reflector H = I - vtvH.
subroutine strmv(UPLO, TRANS, DIAG, N, A, LDA, X, INCX)
STRMV
subroutine sgemv(TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY)
SGEMV