225 $ HOUS2, LHOUS2, WORK, LWORK, INFO )
235 INTEGER N, LDA, LWORK, LHOUS2, INFO
239 REAL A( LDA, * ), TAU( * ),
240 $ hous2( * ), work( * )
246 LOGICAL LQUERY, UPPER, WANTQ
247 INTEGER KD, IB, LWMIN, LHMIN, LWRK, LDAB, WPOS, ABPOS
255 EXTERNAL lsame, ilaenv2stage
262 wantq = lsame( vect,
'V' )
263 upper = lsame( uplo,
'U' )
264 lquery = ( lwork.EQ.-1 ) .OR. ( lhous2.EQ.-1 )
268 kd = ilaenv2stage( 1,
'SSYTRD_2STAGE', vect, n, -1, -1,
270 ib = ilaenv2stage( 2,
'SSYTRD_2STAGE', vect, n, kd, -1,
276 lhmin = ilaenv2stage( 3,
'SSYTRD_2STAGE', vect, n, kd, ib,
278 lwmin = ilaenv2stage( 4,
'SSYTRD_2STAGE', vect, n, kd, ib,
282 IF( .NOT.lsame( vect,
'N' ) )
THEN
284 ELSE IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
286 ELSE IF( n.LT.0 )
THEN
288 ELSE IF( lda.LT.max( 1, n ) )
THEN
290 ELSE IF( lhous2.LT.lhmin .AND. .NOT.lquery )
THEN
292 ELSE IF( lwork.LT.lwmin .AND. .NOT.lquery )
THEN
297 hous2( 1 ) = real( lhmin )
298 work( 1 ) = real( lwmin )
302 CALL xerbla(
'SSYTRD_2STAGE', -info )
304 ELSE IF( lquery )
THEN
320 wpos = abpos + ldab*n
321 CALL ssytrd_sy2sb( uplo, n, kd, a, lda, work( abpos ), ldab,
322 $ tau, work( wpos ), lwrk, info )
324 CALL xerbla(
'SSYTRD_SY2SB', -info )
328 $ work( abpos ), ldab, d, e,
329 $ hous2, lhous2, work( wpos ), lwrk, info )
331 CALL xerbla(
'SSYTRD_SB2ST', -info )
336 work( 1 ) = real( lwmin )
subroutine ssytrd_2stage(vect, uplo, n, a, lda, d, e, tau, hous2, lhous2, work, lwork, info)
SSYTRD_2STAGE
subroutine ssytrd_sb2st(stage1, vect, uplo, n, kd, ab, ldab, d, e, hous, lhous, work, lwork, info)
SSYTRD_SB2ST reduces a real symmetric band matrix A to real symmetric tridiagonal form T
subroutine ssytrd_sy2sb(uplo, n, kd, a, lda, ab, ldab, tau, work, lwork, info)
SSYTRD_SY2SB