117 SUBROUTINE zppcon( UPLO, N, AP, ANORM, RCOND, WORK, RWORK, INFO )
126 DOUBLE PRECISION ANORM, RCOND
129 DOUBLE PRECISION RWORK( * )
130 COMPLEX*16 AP( * ), WORK( * )
136 DOUBLE PRECISION ONE, ZERO
137 parameter( one = 1.0d+0, zero = 0.0d+0 )
143 DOUBLE PRECISION AINVNM, SCALE, SCALEL, SCALEU, SMLNUM
152 DOUBLE PRECISION DLAMCH
153 EXTERNAL lsame, izamax, dlamch
159 INTRINSIC abs, dble, dimag
162 DOUBLE PRECISION CABS1
165 cabs1( zdum ) = abs( dble( zdum ) ) + abs( dimag( zdum ) )
172 upper = lsame( uplo,
'U' )
173 IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
175 ELSE IF( n.LT.0 )
THEN
177 ELSE IF( anorm.LT.zero )
THEN
181 CALL xerbla(
'ZPPCON', -info )
191 ELSE IF( anorm.EQ.zero )
THEN
195 smlnum = dlamch(
'Safe minimum' )
202 CALL zlacn2( n, work( n+1 ), work, ainvnm, kase, isave )
208 CALL zlatps(
'Upper',
'Conjugate transpose',
'Non-unit',
209 $ normin, n, ap, work, scalel, rwork, info )
214 CALL zlatps(
'Upper',
'No transpose',
'Non-unit', normin, n,
215 $ ap, work, scaleu, rwork, info )
220 CALL zlatps(
'Lower',
'No transpose',
'Non-unit', normin, n,
221 $ ap, work, scalel, rwork, info )
226 CALL zlatps(
'Lower',
'Conjugate transpose',
'Non-unit',
227 $ normin, n, ap, work, scaleu, rwork, info )
232 scale = scalel*scaleu
233 IF( scale.NE.one )
THEN
234 ix = izamax( n, work, 1 )
235 IF( scale.LT.cabs1( work( ix ) )*smlnum .OR. scale.EQ.zero )
237 CALL zdrscl( n, scale, work, 1 )
245 $ rcond = ( one / ainvnm ) / anorm
subroutine xerbla(SRNAME, INFO)
XERBLA
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 zdrscl(N, SA, SX, INCX)
ZDRSCL multiplies a vector by the reciprocal of a real scalar.
subroutine zppcon(UPLO, N, AP, ANORM, RCOND, WORK, RWORK, INFO)
ZPPCON