138 SUBROUTINE chpev( JOBZ, UPLO, N, AP, W, Z, LDZ, WORK, RWORK,
151 REAL rwork( * ), w( * )
152 COMPLEX ap( * ), work( * ), z( ldz, * )
159 parameter( zero = 0.0e0, one = 1.0e0 )
163 INTEGER iinfo, imax, inde, indrwk, indtau, indwrk,
165 REAL anrm, bignum, eps, rmax, rmin, safmin, sigma,
184 wantz =
lsame( jobz,
'V' )
187 IF( .NOT.( wantz .OR.
lsame( jobz,
'N' ) ) )
THEN
189 ELSE IF( .NOT.(
lsame( uplo,
'L' ) .OR.
lsame( uplo,
'U' ) ) )
192 ELSE IF( n.LT.0 )
THEN
194 ELSE IF( ldz.LT.1 .OR. ( wantz .AND. ldz.LT.n ) )
THEN
199 CALL
xerbla(
'CHPEV ', -info )
218 safmin =
slamch(
'Safe minimum' )
219 eps =
slamch(
'Precision' )
220 smlnum = safmin / eps
221 bignum = one / smlnum
222 rmin = sqrt( smlnum )
223 rmax = sqrt( bignum )
227 anrm =
clanhp(
'M', uplo, n, ap, rwork )
229 IF( anrm.GT.zero .AND. anrm.LT.rmin )
THEN
232 ELSE IF( anrm.GT.rmax )
THEN
236 IF( iscale.EQ.1 )
THEN
237 CALL
csscal( ( n*( n+1 ) ) / 2, sigma, ap, 1 )
244 CALL
chptrd( uplo, n, ap, w, rwork( inde ), work( indtau ),
250 IF( .NOT.wantz )
THEN
251 CALL
ssterf( n, w, rwork( inde ), info )
254 CALL
cupgtr( uplo, n, ap, work( indtau ), z, ldz,
255 $ work( indwrk ), iinfo )
257 CALL
csteqr( jobz, n, w, rwork( inde ), z, ldz,
258 $ rwork( indrwk ), info )
263 IF( iscale.EQ.1 )
THEN
269 CALL
sscal( imax, one / sigma, w, 1 )
real function clanhp(NORM, UPLO, N, AP, WORK)
CLANHP returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex Hermitian matrix supplied in packed form.
subroutine chptrd(UPLO, N, AP, D, E, TAU, INFO)
CHPTRD
subroutine xerbla(SRNAME, INFO)
XERBLA
logical function lsame(CA, CB)
LSAME
subroutine csteqr(COMPZ, N, D, E, Z, LDZ, WORK, INFO)
CSTEQR
real function slamch(CMACH)
SLAMCH
subroutine cupgtr(UPLO, N, AP, TAU, Q, LDQ, WORK, INFO)
CUPGTR
subroutine csscal(N, SA, CX, INCX)
CSSCAL
subroutine chpev(JOBZ, UPLO, N, AP, W, Z, LDZ, WORK, RWORK, INFO)
CHPEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrice...
subroutine ssterf(N, D, E, INFO)
SSTERF
subroutine sscal(N, SA, SX, INCX)
SSCAL