154 SUBROUTINE zpbstf( UPLO, N, KD, AB, LDAB, INFO )
163 INTEGER INFO, KD, LDAB, N
166 COMPLEX*16 AB( ldab, * )
172 DOUBLE PRECISION ONE, ZERO
173 parameter ( one = 1.0d+0, zero = 0.0d+0 )
177 INTEGER J, KLD, KM, M
188 INTRINSIC dble, max, min, sqrt
195 upper = lsame( uplo,
'U' )
196 IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
198 ELSE IF( n.LT.0 )
THEN
200 ELSE IF( kd.LT.0 )
THEN
202 ELSE IF( ldab.LT.kd+1 )
THEN
206 CALL xerbla(
'ZPBSTF', -info )
215 kld = max( 1, ldab-1 )
225 DO 10 j = n, m + 1, -1
229 ajj = dble( ab( kd+1, j ) )
230 IF( ajj.LE.zero )
THEN
241 CALL zdscal( km, one / ajj, ab( kd+1-km, j ), 1 )
242 CALL zher(
'Upper', km, -one, ab( kd+1-km, j ), 1,
243 $ ab( kd+1, j-km ), kld )
252 ajj = dble( ab( kd+1, j ) )
253 IF( ajj.LE.zero )
THEN
265 CALL zdscal( km, one / ajj, ab( kd, j+1 ), kld )
266 CALL zlacgv( km, ab( kd, j+1 ), kld )
267 CALL zher(
'Upper', km, -one, ab( kd, j+1 ), kld,
268 $ ab( kd+1, j+1 ), kld )
269 CALL zlacgv( km, ab( kd, j+1 ), kld )
276 DO 30 j = n, m + 1, -1
280 ajj = dble( ab( 1, j ) )
281 IF( ajj.LE.zero )
THEN
292 CALL zdscal( km, one / ajj, ab( km+1, j-km ), kld )
293 CALL zlacgv( km, ab( km+1, j-km ), kld )
294 CALL zher(
'Lower', km, -one, ab( km+1, j-km ), kld,
295 $ ab( 1, j-km ), kld )
296 CALL zlacgv( km, ab( km+1, j-km ), kld )
305 ajj = dble( ab( 1, j ) )
306 IF( ajj.LE.zero )
THEN
318 CALL zdscal( km, one / ajj, ab( 2, j ), 1 )
319 CALL zher(
'Lower', km, -one, ab( 2, j ), 1,
320 $ ab( 1, j+1 ), kld )
subroutine zpbstf(UPLO, N, KD, AB, LDAB, INFO)
ZPBSTF
subroutine zher(UPLO, N, ALPHA, X, INCX, A, LDA)
ZHER
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine zlacgv(N, X, INCX)
ZLACGV conjugates a complex vector.
subroutine zdscal(N, DA, ZX, INCX)
ZDSCAL