115 SUBROUTINE zppcon( UPLO, N, AP, ANORM, RCOND, WORK, RWORK,
125 DOUBLE PRECISION ANORM, RCOND
128 DOUBLE PRECISION RWORK( * )
129 COMPLEX*16 AP( * ), WORK( * )
135 DOUBLE PRECISION ONE, ZERO
136 parameter( one = 1.0d+0, zero = 0.0d+0 )
142 DOUBLE PRECISION AINVNM, SCALE, SCALEL, SCALEU, SMLNUM
151 DOUBLE PRECISION DLAMCH
152 EXTERNAL lsame, izamax, dlamch
158 INTRINSIC abs, dble, dimag
161 DOUBLE PRECISION CABS1
164 cabs1( zdum ) = abs( dble( zdum ) ) + abs( dimag( zdum ) )
171 upper = lsame( uplo,
'U' )
172 IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
174 ELSE IF( n.LT.0 )
THEN
176 ELSE IF( anorm.LT.zero )
THEN
180 CALL xerbla(
'ZPPCON', -info )
190 ELSE IF( anorm.EQ.zero )
THEN
194 smlnum = dlamch(
'Safe minimum' )
201 CALL zlacn2( n, work( n+1 ), work, ainvnm, kase, isave )
207 CALL zlatps(
'Upper',
'Conjugate transpose',
'Non-unit',
208 $ normin, n, ap, work, scalel, rwork, info )
213 CALL zlatps(
'Upper',
'No transpose',
'Non-unit', normin,
215 $ ap, work, scaleu, rwork, info )
220 CALL zlatps(
'Lower',
'No transpose',
'Non-unit', normin,
222 $ ap, work, scalel, rwork, info )
227 CALL zlatps(
'Lower',
'Conjugate transpose',
'Non-unit',
228 $ normin, n, ap, work, scaleu, rwork, info )
233 scale = scalel*scaleu
234 IF( scale.NE.one )
THEN
235 ix = izamax( n, work, 1 )
236 IF( scale.LT.cabs1( work( ix ) )*smlnum .OR. scale.EQ.zero )
238 CALL zdrscl( n, scale, work, 1 )
246 $ rcond = ( one / ainvnm ) / anorm
subroutine zlacn2(n, v, x, est, kase, isave)
ZLACN2 estimates the 1-norm of a square matrix, using reverse communication for evaluating matrix-vec...
subroutine zlatps(uplo, trans, diag, normin, n, ap, x, scale, cnorm, info)
ZLATPS solves a triangular system of equations with the matrix held in packed storage.
subroutine zppcon(uplo, n, ap, anorm, rcond, work, rwork, info)
ZPPCON
subroutine zdrscl(n, sa, sx, incx)
ZDRSCL multiplies a vector by the reciprocal of a real scalar.