119 SUBROUTINE zppcon( UPLO, N, AP, ANORM, RCOND, WORK, RWORK, INFO )
129 DOUBLE PRECISION ANORM, RCOND
132 DOUBLE PRECISION RWORK( * )
133 COMPLEX*16 AP( * ), WORK( * )
139 DOUBLE PRECISION ONE, ZERO
140 parameter ( one = 1.0d+0, zero = 0.0d+0 )
146 DOUBLE PRECISION AINVNM, SCALE, SCALEL, SCALEU, SMLNUM
155 DOUBLE PRECISION DLAMCH
156 EXTERNAL lsame, izamax, dlamch
162 INTRINSIC abs, dble, dimag
165 DOUBLE PRECISION CABS1
168 cabs1( zdum ) = abs( dble( zdum ) ) + abs( dimag( zdum ) )
175 upper = lsame( uplo,
'U' )
176 IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
178 ELSE IF( n.LT.0 )
THEN
180 ELSE IF( anorm.LT.zero )
THEN
184 CALL xerbla(
'ZPPCON', -info )
194 ELSE IF( anorm.EQ.zero )
THEN
198 smlnum = dlamch(
'Safe minimum' )
205 CALL zlacn2( n, work( n+1 ), work, ainvnm, kase, isave )
211 CALL zlatps(
'Upper',
'Conjugate transpose',
'Non-unit',
212 $ normin, n, ap, work, scalel, rwork, info )
217 CALL zlatps(
'Upper',
'No transpose',
'Non-unit', normin, n,
218 $ ap, work, scaleu, rwork, info )
223 CALL zlatps(
'Lower',
'No transpose',
'Non-unit', normin, n,
224 $ ap, work, scalel, rwork, info )
229 CALL zlatps(
'Lower',
'Conjugate transpose',
'Non-unit',
230 $ normin, n, ap, work, scaleu, rwork, info )
235 scale = scalel*scaleu
236 IF( scale.NE.one )
THEN
237 ix = izamax( n, work, 1 )
238 IF( scale.LT.cabs1( work( ix ) )*smlnum .OR. scale.EQ.zero )
240 CALL zdrscl( n, scale, work, 1 )
248 $ 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 zdrscl(N, SA, SX, INCX)
ZDRSCL multiplies a vector by the reciprocal of a real scalar.
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 xerbla(SRNAME, INFO)
XERBLA
subroutine zppcon(UPLO, N, AP, ANORM, RCOND, WORK, RWORK, INFO)
ZPPCON