146 SUBROUTINE sgbtf2( M, N, KL, KU, AB, LDAB, IPIV, INFO )
154 INTEGER INFO, KL, KU, LDAB, M, N
165 parameter( one = 1.0e+0, zero = 0.0e+0 )
168 INTEGER I, J, JP, JU, KM, KV
192 ELSE IF( n.LT.0 )
THEN
194 ELSE IF( kl.LT.0 )
THEN
196 ELSE IF( ku.LT.0 )
THEN
198 ELSE IF( ldab.LT.kl+kv+1 )
THEN
202 CALL
xerbla(
'SGBTF2', -info )
208 IF( m.EQ.0 .OR. n.EQ.0 )
215 DO 20 j = ku + 2, min( kv, n )
216 DO 10 i = kv - j + 2, kl
226 DO 40 j = 1, min( m, n )
240 jp = isamax( km+1, ab( kv+1, j ), 1 )
241 ipiv( j ) = jp + j - 1
242 IF( ab( kv+jp, j ).NE.zero )
THEN
243 ju = max( ju, min( j+ku+jp-1, n ) )
248 $ CALL
sswap( ju-j+1, ab( kv+jp, j ), ldab-1,
249 $ ab( kv+1, j ), ldab-1 )
255 CALL
sscal( km, one / ab( kv+1, j ), ab( kv+2, j ), 1 )
260 $ CALL
sger( km, ju-j, -one, ab( kv+2, j ), 1,
261 $ ab( kv, j+1 ), ldab-1, ab( kv+1, j+1 ),
subroutine sswap(N, SX, INCX, SY, INCY)
SSWAP
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine sger(M, N, ALPHA, X, INCX, Y, INCY, A, LDA)
SGER
subroutine sgbtf2(M, N, KL, KU, AB, LDAB, IPIV, INFO)
SGBTF2 computes the LU factorization of a general band matrix using the unblocked version of the algo...
subroutine sscal(N, SA, SX, INCX)
SSCAL