131 SUBROUTINE sspev( JOBZ, UPLO, N, AP, W, Z, LDZ, WORK, INFO )
143 REAL AP( * ), W( * ), WORK( * ), Z( ldz, * )
150 parameter ( zero = 0.0e0, one = 1.0e0 )
154 INTEGER IINFO, IMAX, INDE, INDTAU, INDWRK, ISCALE
155 REAL ANRM, BIGNUM, EPS, RMAX, RMIN, SAFMIN, SIGMA,
161 EXTERNAL lsame, slamch, slansp
173 wantz = lsame( jobz,
'V' )
176 IF( .NOT.( wantz .OR. lsame( jobz,
'N' ) ) )
THEN
178 ELSE IF( .NOT.( lsame( uplo,
'U' ) .OR. lsame( uplo,
'L' ) ) )
181 ELSE IF( n.LT.0 )
THEN
183 ELSE IF( ldz.LT.1 .OR. ( wantz .AND. ldz.LT.n ) )
THEN
188 CALL xerbla(
'SSPEV ', -info )
206 safmin = slamch(
'Safe minimum' )
207 eps = slamch(
'Precision' )
208 smlnum = safmin / eps
209 bignum = one / smlnum
210 rmin = sqrt( smlnum )
211 rmax = sqrt( bignum )
215 anrm = slansp(
'M', uplo, n, ap, work )
217 IF( anrm.GT.zero .AND. anrm.LT.rmin )
THEN
220 ELSE IF( anrm.GT.rmax )
THEN
224 IF( iscale.EQ.1 )
THEN
225 CALL sscal( ( n*( n+1 ) ) / 2, sigma, ap, 1 )
232 CALL ssptrd( uplo, n, ap, w, work( inde ), work( indtau ), iinfo )
237 IF( .NOT.wantz )
THEN
238 CALL ssterf( n, w, work( inde ), info )
241 CALL sopgtr( uplo, n, ap, work( indtau ), z, ldz,
242 $ work( indwrk ), iinfo )
243 CALL ssteqr( jobz, n, w, work( inde ), z, ldz, work( indtau ),
249 IF( iscale.EQ.1 )
THEN
255 CALL sscal( imax, one / sigma, w, 1 )
subroutine sspev(JOBZ, UPLO, N, AP, W, Z, LDZ, WORK, INFO)
SSPEV computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrice...
subroutine ssptrd(UPLO, N, AP, D, E, TAU, INFO)
SSPTRD
subroutine ssteqr(COMPZ, N, D, E, Z, LDZ, WORK, INFO)
SSTEQR
subroutine sopgtr(UPLO, N, AP, TAU, Q, LDQ, WORK, INFO)
SOPGTR
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine sscal(N, SA, SX, INCX)
SSCAL
subroutine ssterf(N, D, E, INFO)
SSTERF