      SUBROUTINE DSTEMR( JOBZ, RANGE, N, D, E, VL, VU, IL, IU,
     $                   M, W, Z, LDZ, NZC, ISUPPZ, TRYRAC, WORK, LWORK,
     $                   IWORK, LIWORK, INFO )
      IMPLICIT NONE
*
*  -- LAPACK computational routine (version 3.1) --
*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
*     November 2006
*
*     .. Scalar Arguments ..
      CHARACTER          JOBZ, RANGE
      LOGICAL            TRYRAC
      INTEGER            IL, INFO, IU, LDZ, NZC, LIWORK, LWORK, M, N
      DOUBLE PRECISION VL, VU
*     ..
*     .. Array Arguments ..
      INTEGER            ISUPPZ( * ), IWORK( * )
      DOUBLE PRECISION   D( * ), E( * ), W( * ), WORK( * )
      DOUBLE PRECISION   Z( LDZ, * )
*     ..
*
*  Purpose
*  =======
*
*  DSTEMR computes selected eigenvalues and, optionally, eigenvectors
*  of a real symmetric tridiagonal matrix T. Any such unreduced matrix has
*  a well defined set of pairwise different real eigenvalues, the corresponding
*  real eigenvectors are pairwise orthogonal.
*
*  The spectrum may be computed either completely or partially by specifying
*  either an interval (VL,VU] or a range of indices IL:IU for the desired
*  eigenvalues.
*
*  Depending on the number of desired eigenvalues, these are computed either
*  by bisection or the dqds algorithm. Numerically orthogonal eigenvectors are
*  computed by the use of various suitable L D L^T factorizations near clusters
*  of close eigenvalues (referred to as RRRs, Relatively Robust
*  Representations). An informal sketch of the algorithm follows.
*
*  For each unreduced block (submatrix) of T,
*     (a) Compute T - sigma I  = L D L^T, so that L and D
*         define all the wanted eigenvalues to high relative accuracy.
*         This means that small relative changes in the entries of D and L
*         cause only small relative changes in the eigenvalues and
*         eigenvectors. The standard (unfactored) representation of the
*         tridiagonal matrix T does not have this property in general.
*     (b) Compute the eigenvalues to suitable accuracy.
*         If the eigenvectors are desired, the algorithm attains full
*         accuracy of the computed eigenvalues only right before
*         the corresponding vectors have to be computed, see steps c) and d).
*     (c) For each cluster of close eigenvalues, select a new
*         shift close to the cluster, find a new factorization, and refine
*         the shifted eigenvalues to suitable accuracy.
*     (d) For each eigenvalue with a large enough relative separation compute
*         the corresponding eigenvector by forming a rank revealing twisted
*         factorization. Go back to (c) for any clusters that remain.
*
*  For more details, see:
*  - Inderjit S. Dhillon and Beresford N. Parlett: "Multiple representations
*    to compute orthogonal eigenvectors of symmetric tridiagonal matrices,"
*    Linear Algebra and its Applications, 387(1), pp. 1-28, August 2004.
*  - Inderjit Dhillon and Beresford Parlett: "Orthogonal Eigenvectors and
*    Relative Gaps," SIAM Journal on Matrix Analysis and Applications, Vol. 25,
*    2004.  Also LAPACK Working Note 154.
*  - Inderjit Dhillon: "A new O(n^2) algorithm for the symmetric
*    tridiagonal eigenvalue/eigenvector problem",
*    Computer Science Division Technical Report No. UCB/CSD-97-971,
*    UC Berkeley, May 1997.
*
*  Notes:
*  1.DSTEMR works only on machines which follow IEEE-754
*  floating-point standard in their handling of infinities and NaNs.
*  This permits the use of efficient inner loops avoiding a check for
*  zero divisors.
*
*  Arguments
*  =========
*
*  JOBZ    (input) CHARACTER*1
*          = 'N':  Compute eigenvalues only;
*          = 'V':  Compute eigenvalues and eigenvectors.
*
*  RANGE   (input) CHARACTER*1
*          = 'A': all eigenvalues will be found.
*          = 'V': all eigenvalues in the half-open interval (VL,VU]
*                 will be found.
*          = 'I': the IL-th through IU-th eigenvalues will be found.
*
*  N       (input) INTEGER
*          The order of the matrix.  N >= 0.
*
*  D       (input/output) DOUBLE PRECISION array, dimension (N)
*          On entry, the N diagonal elements of the tridiagonal matrix
*          T. On exit, D is overwritten.
*
*  E       (input/output) DOUBLE PRECISION array, dimension (N)
*          On entry, the (N-1) subdiagonal elements of the tridiagonal
*          matrix T in elements 1 to N-1 of E. E(N) need not be set on
*          input, but is used internally as workspace.
*          On exit, E is overwritten.
*
*  VL      (input) DOUBLE PRECISION
*  VU      (input) DOUBLE PRECISION
*          If RANGE='V', the lower and upper bounds of the interval to
*          be searched for eigenvalues. VL < VU.
*          Not referenced if RANGE = 'A' or 'I'.
*
*  IL      (input) INTEGER
*  IU      (input) INTEGER
*          If RANGE='I', the indices (in ascending order) of the
*          smallest and largest eigenvalues to be returned.
*          1 <= IL <= IU <= N, if N > 0.
*          Not referenced if RANGE = 'A' or 'V'.
*
*  M       (output) INTEGER
*          The total number of eigenvalues found.  0 <= M <= N.
*          If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1.
*
*  W       (output) DOUBLE PRECISION array, dimension (N)
*          The first M elements contain the selected eigenvalues in
*          ascending order.
*
*  Z       (output) DOUBLE PRECISION array, dimension (LDZ, max(1,M) )
*          If JOBZ = 'V', and if INFO = 0, then the first M columns of Z
*          contain the orthonormal eigenvectors of the matrix T
*          corresponding to the selected eigenvalues, with the i-th
*          column of Z holding the eigenvector associated with W(i).
*          If JOBZ = 'N', then Z is not referenced.
*          Note: the user must ensure that at least max(1,M) columns are
*          supplied in the array Z; if RANGE = 'V', the exact value of M
*          is not known in advance and can be computed with a workspace
*          query by setting NZC = -1, see below.
*
*  LDZ     (input) INTEGER
*          The leading dimension of the array Z.  LDZ >= 1, and if
*          JOBZ = 'V', then LDZ >= max(1,N).
*
*  NZC     (input) INTEGER
*          The number of eigenvectors to be held in the array Z.
*          If RANGE = 'A', then NZC >= max(1,N).
*          If RANGE = 'V', then NZC >= the number of eigenvalues in (VL,VU].
*          If RANGE = 'I', then NZC >= IU-IL+1.
*          If NZC = -1, then a workspace query is assumed; the
*          routine calculates the number of columns of the array Z that
*          are needed to hold the eigenvectors.
*          This value is returned as the first entry of the Z array, and
*          no error message related to NZC is issued by XERBLA.
*
*  ISUPPZ  (output) INTEGER ARRAY, dimension ( 2*max(1,M) )
*          The support of the eigenvectors in Z, i.e., the indices
*          indicating the nonzero elements in Z. The i-th computed eigenvector
*          is nonzero only in elements ISUPPZ( 2*i-1 ) through
*          ISUPPZ( 2*i ). This is relevant in the case when the matrix
*          is split. ISUPPZ is only accessed when JOBZ is 'V' and N > 0.
*
*  TRYRAC  (input/output) LOGICAL
*          If TRYRAC.EQ..TRUE., indicates that the code should check whether
*          the tridiagonal matrix defines its eigenvalues to high relative
*          accuracy.  If so, the code uses relative-accuracy preserving
*          algorithms that might be (a bit) slower depending on the matrix.
*          If the matrix does not define its eigenvalues to high relative
*          accuracy, the code can uses possibly faster algorithms.
*          If TRYRAC.EQ..FALSE., the code is not required to guarantee
*          relatively accurate eigenvalues and can use the fastest possible
*          techniques.
*          On exit, a .TRUE. TRYRAC will be set to .FALSE. if the matrix
*          does not define its eigenvalues to high relative accuracy.
*
*  WORK    (workspace/output) DOUBLE PRECISION array, dimension (LWORK)
*          On exit, if INFO = 0, WORK(1) returns the optimal
*          (and minimal) LWORK.
*
*  LWORK   (input) INTEGER
*          The dimension of the array WORK. LWORK >= max(1,18*N)
*          if JOBZ = 'V', and LWORK >= max(1,12*N) if JOBZ = 'N'.
*          If LWORK = -1, then a workspace query is assumed; the routine
*          only calculates the optimal size of the WORK array, returns
*          this value as the first entry of the WORK array, and no error
*          message related to LWORK is issued by XERBLA.
*
*  IWORK   (workspace/output) INTEGER array, dimension (LIWORK)
*          On exit, if INFO = 0, IWORK(1) returns the optimal LIWORK.
*
*  LIWORK  (input) INTEGER
*          The dimension of the array IWORK.  LIWORK >= max(1,10*N)
*          if the eigenvectors are desired, and LIWORK >= max(1,8*N)
*          if only the eigenvalues are to be computed.
*          If LIWORK = -1, then a workspace query is assumed; the
*          routine only calculates the optimal size of the IWORK array,
*          returns this value as the first entry of the IWORK array, and
*          no error message related to LIWORK is issued by XERBLA.
*
*  INFO    (output) INTEGER
*          On exit, INFO
*          = 0:  successful exit
*          < 0:  if INFO = -i, the i-th argument had an illegal value
*          > 0:  if INFO = 1X, internal error in DLARRE,
*                if INFO = 2X, internal error in DLARRV.
*                Here, the digit X = ABS( IINFO ) < 10, where IINFO is
*                the nonzero error code returned by DLARRE or
*                DLARRV, respectively.
*
*
*  Further Details
*  ===============
*
*  Based on contributions by
*     Beresford Parlett, University of California, Berkeley, USA
*     Jim Demmel, University of California, Berkeley, USA
*     Inderjit Dhillon, University of Texas, Austin, USA
*     Osni Marques, LBNL/NERSC, USA
*     Christof Voemel, University of California, Berkeley, USA
*
*  =====================================================================
*
*     .. Parameters ..
      DOUBLE PRECISION   ZERO, ONE, FOUR, MINRGP
      PARAMETER          ( ZERO = 0.0D0, ONE = 1.0D0,
     $                     FOUR = 4.0D0,
     $                     MINRGP = 1.0D-3 )
*     ..
*     .. Local Scalars ..
      LOGICAL            ALLEIG, INDEIG, LQUERY, VALEIG, WANTZ, ZQUERY
      INTEGER            I, IBEGIN, IEND, IFIRST, IIL, IINDBL, IINDW,
     $                   IINDWK, IINFO, IINSPL, IIU, ILAST, IN, INDD,
     $                   INDE2, INDERR, INDGP, INDGRS, INDWRK, ITMP,
     $                   ITMP2, J, JBLK, JJ, LIWMIN, LWMIN, NSPLIT,
     $                   NZCMIN, OFFSET, WBEGIN, WEND
      DOUBLE PRECISION   BIGNUM, CS, EPS, PIVMIN, R1, R2, RMAX, RMIN,
     $                   RTOL1, RTOL2, SAFMIN, SCALE, SMLNUM, SN,
     $                   THRESH, TMP, TNRM, WL, WU
*     ..
*     ..
*     .. External Functions ..
      LOGICAL            LSAME
      DOUBLE PRECISION   DLAMCH, DLANST
      EXTERNAL           LSAME, DLAMCH, DLANST
*     ..
*     .. External Subroutines ..
      EXTERNAL           DCOPY, DLAE2, DLAEV2, DLARRC, DLARRE, DLARRJ,
     $                   DLARRR, DLARRV, DLASRT, DSCAL, DSWAP, XERBLA
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          MAX, MIN, SQRT


*     ..
*     .. Executable Statements ..
*
*     Test the input parameters.
*
      WANTZ = LSAME( JOBZ, 'V' )
      ALLEIG = LSAME( RANGE, 'A' )
      VALEIG = LSAME( RANGE, 'V' )
      INDEIG = LSAME( RANGE, 'I' )
*
      LQUERY = ( ( LWORK.EQ.-1 ).OR.( LIWORK.EQ.-1 ) )
      ZQUERY = ( NZC.EQ.-1 )
      TRYRAC = ( INFO.NE.0 )

*     DSTEMR needs WORK of size 6*N, IWORK of size 3*N.
*     In addition, DLARRE needs WORK of size 6*N, IWORK of size 5*N.
*     Furthermore, DLARRV needs WORK of size 12*N, IWORK of size 7*N.
      IF( WANTZ ) THEN
         LWMIN = 18*N
         LIWMIN = 10*N
      ELSE
*        need less workspace if only the eigenvalues are wanted
         LWMIN = 12*N
         LIWMIN = 8*N
      ENDIF

      WL = ZERO
      WU = ZERO
      IIL = 0
      IIU = 0

      IF( VALEIG ) THEN
*        We do not reference VL, VU in the cases RANGE = 'I','A'
*        The interval (WL, WU] contains all the wanted eigenvalues.
*        It is either given by the user or computed in DLARRE.
         WL = VL
         WU = VU
      ELSEIF( INDEIG ) THEN
*        We do not reference IL, IU in the cases RANGE = 'V','A'
         IIL = IL
         IIU = IU
      ENDIF
*
      INFO = 0
      IF( .NOT.( WANTZ .OR. LSAME( JOBZ, 'N' ) ) ) THEN
         INFO = -1
      ELSE IF( .NOT.( ALLEIG .OR. VALEIG .OR. INDEIG ) ) THEN
         INFO = -2
      ELSE IF( N.LT.0 ) THEN
         INFO = -3
      ELSE IF( VALEIG .AND. N.GT.0 .AND. WU.LE.WL ) THEN
         INFO = -7
      ELSE IF( INDEIG .AND. ( IIL.LT.1 .OR. IIL.GT.N ) ) THEN
         INFO = -8
      ELSE IF( INDEIG .AND. ( IIU.LT.IIL .OR. IIU.GT.N ) ) THEN
         INFO = -9
      ELSE IF( LDZ.LT.1 .OR. ( WANTZ .AND. LDZ.LT.N ) ) THEN
         INFO = -13
      ELSE IF( LWORK.LT.LWMIN .AND. .NOT.LQUERY ) THEN
         INFO = -17
      ELSE IF( LIWORK.LT.LIWMIN .AND. .NOT.LQUERY ) THEN
         INFO = -19
      END IF
*
*     Get machine constants.
*
      SAFMIN = DLAMCH( 'Safe minimum' )
      EPS = DLAMCH( 'Precision' )
      SMLNUM = SAFMIN / EPS
      BIGNUM = ONE / SMLNUM
      RMIN = SQRT( SMLNUM )
      RMAX = MIN( SQRT( BIGNUM ), ONE / SQRT( SQRT( SAFMIN ) ) )
*
      IF( INFO.EQ.0 ) THEN
         WORK( 1 ) = LWMIN
         IWORK( 1 ) = LIWMIN
*
         IF( WANTZ .AND. ALLEIG ) THEN
            NZCMIN = N
         ELSE IF( WANTZ .AND. VALEIG ) THEN
            CALL DLARRC( 'T', N, VL, VU, D, E, SAFMIN,
     $                            NZCMIN, ITMP, ITMP2, INFO )
         ELSE IF( WANTZ .AND. INDEIG ) THEN
            NZCMIN = IIU-IIL+1
         ELSE
*           WANTZ .EQ. FALSE.
            NZCMIN = 0
         ENDIF
         IF( ZQUERY .AND. INFO.EQ.0 ) THEN
            Z( 1,1 ) = NZCMIN
         ELSE IF( NZC.LT.NZCMIN .AND. .NOT.ZQUERY ) THEN
            INFO = -14
         END IF
      END IF

      IF( INFO.NE.0 ) THEN
*
         CALL XERBLA( 'DSTEMR', -INFO )
*
         RETURN
      ELSE IF( LQUERY .OR. ZQUERY ) THEN
         RETURN
      END IF
*
*     Handle N = 0, 1, and 2 cases immediately
*
      M = 0
      IF( N.EQ.0 )
     $   RETURN
*
      IF( N.EQ.1 ) THEN
         IF( ALLEIG .OR. INDEIG ) THEN
            M = 1
            W( 1 ) = D( 1 )
         ELSE
            IF( WL.LT.D( 1 ) .AND. WU.GE.D( 1 ) ) THEN
               M = 1
               W( 1 ) = D( 1 )
            END IF
         END IF
         IF( WANTZ.AND.(.NOT.ZQUERY) ) THEN
            Z( 1, 1 ) = ONE
            ISUPPZ(1) = 1
            ISUPPZ(2) = 1
         END IF
         RETURN
      END IF
*
      IF( N.EQ.2 ) THEN
         IF( .NOT.WANTZ ) THEN
            CALL DLAE2( D(1), E(1), D(2), R1, R2 )
         ELSE IF( WANTZ.AND.(.NOT.ZQUERY) ) THEN
            CALL DLAEV2( D(1), E(1), D(2), R1, R2, CS, SN )
         END IF
         IF( ALLEIG.OR.
     $      (VALEIG.AND.(R2.GT.WL).AND.
     $                  (R2.LE.WU)).OR.
     $      (INDEIG.AND.(IIL.EQ.1)) ) THEN
            M = M+1
            W( M ) = R2
            IF( WANTZ.AND.(.NOT.ZQUERY) ) THEN
               Z( 1, M ) = -SN
               Z( 2, M ) = CS
*              Note: At most one of SN and CS can be zero.
               IF (SN.NE.ZERO) THEN
                  IF (CS.NE.ZERO) THEN
                     ISUPPZ(2*M-1) = 1
                     ISUPPZ(2*M-1) = 2
                  ELSE
                     ISUPPZ(2*M-1) = 1
                     ISUPPZ(2*M-1) = 1
                  END IF
               ELSE
                  ISUPPZ(2*M-1) = 2
                  ISUPPZ(2*M) = 2
               END IF
            ENDIF
         ENDIF
         IF( ALLEIG.OR.
     $      (VALEIG.AND.(R1.GT.WL).AND.
     $                  (R1.LE.WU)).OR.
     $      (INDEIG.AND.(IIU.EQ.2)) ) THEN
            M = M+1
            W( M ) = R1
            IF( WANTZ.AND.(.NOT.ZQUERY) ) THEN
               Z( 1, M ) = CS
               Z( 2, M ) = SN
*              Note: At most one of SN and CS can be zero.
               IF (SN.NE.ZERO) THEN
                  IF (CS.NE.ZERO) THEN
                     ISUPPZ(2*M-1) = 1
                     ISUPPZ(2*M-1) = 2
                  ELSE
                     ISUPPZ(2*M-1) = 1
                     ISUPPZ(2*M-1) = 1
                  END IF
               ELSE
                  ISUPPZ(2*M-1) = 2
                  ISUPPZ(2*M) = 2
               END IF
            ENDIF
         ENDIF
         RETURN
      END IF

*     Continue with general N

      INDGRS = 1
      INDERR = 2*N + 1
      INDGP = 3*N + 1
      INDD = 4*N + 1
      INDE2 = 5*N + 1
      INDWRK = 6*N + 1
*
      IINSPL = 1
      IINDBL = N + 1
      IINDW = 2*N + 1
      IINDWK = 3*N + 1
*
*     Scale matrix to allowable range, if necessary.
*     The allowable range is related to the PIVMIN parameter; see the
*     comments in DLARRD.  The preference for scaling small values
*     up is heuristic; we expect users' matrices not to be close to the
*     RMAX threshold.
*
      SCALE = ONE
      TNRM = DLANST( 'M', N, D, E )
      IF( TNRM.GT.ZERO .AND. TNRM.LT.RMIN ) THEN
         SCALE = RMIN / TNRM
      ELSE IF( TNRM.GT.RMAX ) THEN
         SCALE = RMAX / TNRM
      END IF
      IF( SCALE.NE.ONE ) THEN
         CALL DSCAL( N, SCALE, D, 1 )
         CALL DSCAL( N-1, SCALE, E, 1 )
         TNRM = TNRM*SCALE
         IF( VALEIG ) THEN
*           If eigenvalues in interval have to be found,
*           scale (WL, WU] accordingly
            WL = WL*SCALE
            WU = WU*SCALE
         ENDIF
      END IF
*
*     Compute the desired eigenvalues of the tridiagonal after splitting
*     into smaller subblocks if the corresponding off-diagonal elements
*     are small
*     THRESH is the splitting parameter for DLARRE
*     A negative THRESH forces the old splitting criterion based on the
*     size of the off-diagonal. A positive THRESH switches to splitting
*     which preserves relative accuracy.
*
      IF( TRYRAC ) THEN
*        Test whether the matrix warrants the more expensive relative approach.
         CALL DLARRR( N, D, E, IINFO )
      ELSE
*        The user does not care about relative accurately eigenvalues
         IINFO = -1
      ENDIF
*     Set the splitting criterion
      IF (IINFO.EQ.0) THEN
         THRESH = EPS
      ELSE
         THRESH = -EPS
*        relative accuracy is desired but T does not guarantee it
         TRYRAC = .FALSE.
      ENDIF
*
      IF( TRYRAC ) THEN
*        Copy original diagonal, needed to guarantee relative accuracy
         CALL DCOPY(N,D,1,WORK(INDD),1)
      ENDIF
*     Store the squares of the offdiagonal values of T
      DO 5 J = 1, N-1
         WORK( INDE2+J-1 ) = E(J)**2
 5    CONTINUE

*     Set the tolerance parameters for bisection
      IF( .NOT.WANTZ ) THEN
*        DLARRE computes the eigenvalues to full precision.
         RTOL1 = FOUR * EPS
         RTOL2 = FOUR * EPS
      ELSE
*        DLARRE computes the eigenvalues to less than full precision.
*        DLARRV will refine the eigenvalue approximations, and we can
*        need less accurate initial bisection in DLARRE.
*        Note: these settings do only affect the subset case and DLARRE
         RTOL1 = SQRT(EPS)
         RTOL2 = MAX( SQRT(EPS)*5.0D-3, FOUR * EPS )
      ENDIF
      CALL DLARRE( RANGE, N, WL, WU, IIL, IIU, D, E,
     $             WORK(INDE2), RTOL1, RTOL2, THRESH, NSPLIT,
     $             IWORK( IINSPL ), M, W, WORK( INDERR ),
     $             WORK( INDGP ), IWORK( IINDBL ),
     $             IWORK( IINDW ), WORK( INDGRS ), PIVMIN,
     $             WORK( INDWRK ), IWORK( IINDWK ), IINFO )
      IF( IINFO.NE.0 ) THEN
         INFO = 10 + ABS( IINFO )
         RETURN
      END IF
*     Note that if RANGE .NE. 'V', DLARRE computes bounds on the desired
*     part of the spectrum. All desired eigenvalues are contained in
*     (WL,WU]


      IF( WANTZ ) THEN
*
*        Compute the desired eigenvectors corresponding to the computed
*        eigenvalues
*
         CALL DLARRV( N, WL, WU, D, E,
     $                PIVMIN, IWORK( IINSPL ), M,
     $                1, M, MINRGP, RTOL1, RTOL2,
     $                W, WORK( INDERR ), WORK( INDGP ), IWORK( IINDBL ),
     $                IWORK( IINDW ), WORK( INDGRS ), Z, LDZ,
     $                ISUPPZ, WORK( INDWRK ), IWORK( IINDWK ), IINFO )
         IF( IINFO.NE.0 ) THEN
            INFO = 20 + ABS( IINFO )
            RETURN
         END IF
      ELSE
*        DLARRE computes eigenvalues of the (shifted) root representation
*        DLARRV returns the eigenvalues of the unshifted matrix.
*        However, if the eigenvectors are not desired by the user, we need
*        to apply the corresponding shifts from DLARRE to obtain the
*        eigenvalues of the original matrix.
         DO 20 J = 1, M
            ITMP = IWORK( IINDBL+J-1 )
            W( J ) = W( J ) + E( IWORK( IINSPL+ITMP-1 ) )
 20      CONTINUE
      END IF
*

      IF ( TRYRAC ) THEN
*        Refine computed eigenvalues so that they are relatively accurate
*        with respect to the original matrix T.
         IBEGIN = 1
         WBEGIN = 1
         DO 39  JBLK = 1, IWORK( IINDBL+M-1 )
            IEND = IWORK( IINSPL+JBLK-1 )
            IN = IEND - IBEGIN + 1
            WEND = WBEGIN - 1
*           check if any eigenvalues have to be refined in this block
 36         CONTINUE
            IF( WEND.LT.M ) THEN
               IF( IWORK( IINDBL+WEND ).EQ.JBLK ) THEN
                  WEND = WEND + 1
                  GO TO 36
               END IF
            END IF
            IF( WEND.LT.WBEGIN ) THEN
               IBEGIN = IEND + 1
               GO TO 39
            END IF

            OFFSET = IWORK(IINDW+WBEGIN-1)-1
            IFIRST = IWORK(IINDW+WBEGIN-1)
            ILAST = IWORK(IINDW+WEND-1)
            RTOL2 = FOUR * EPS
            CALL DLARRJ( IN,
     $                   WORK(INDD+IBEGIN-1), WORK(INDE2+IBEGIN-1),
     $                   IFIRST, ILAST, RTOL2, OFFSET, W(WBEGIN),
     $                   WORK( INDERR+WBEGIN-1 ),
     $                   WORK( INDWRK ), IWORK( IINDWK ), PIVMIN,
     $                   TNRM, IINFO )
            IBEGIN = IEND + 1
            WBEGIN = WEND + 1
 39      CONTINUE
      ENDIF
*
*     If matrix was scaled, then rescale eigenvalues appropriately.
*
      IF( SCALE.NE.ONE ) THEN
         CALL DSCAL( M, ONE / SCALE, W, 1 )
      END IF
*
*     If eigenvalues are not in increasing order, then sort them,
*     possibly along with eigenvectors.
*
      IF( NSPLIT.GT.1 ) THEN
         IF( .NOT. WANTZ ) THEN
            CALL DLASRT( 'I', M, W, IINFO )
            IF( IINFO.NE.0 ) THEN
               INFO = 3
               RETURN
            END IF
         ELSE
            DO 60 J = 1, M - 1
               I = 0
               TMP = W( J )
               DO 50 JJ = J + 1, M
                  IF( W( JJ ).LT.TMP ) THEN
                     I = JJ
                     TMP = W( JJ )
                  END IF
 50            CONTINUE
               IF( I.NE.0 ) THEN
                  W( I ) = W( J )
                  W( J ) = TMP
                  IF( WANTZ ) THEN
                     CALL DSWAP( N, Z( 1, I ), 1, Z( 1, J ), 1 )
                     ITMP = ISUPPZ( 2*I-1 )
                     ISUPPZ( 2*I-1 ) = ISUPPZ( 2*J-1 )
                     ISUPPZ( 2*J-1 ) = ITMP
                     ITMP = ISUPPZ( 2*I )
                     ISUPPZ( 2*I ) = ISUPPZ( 2*J )
                     ISUPPZ( 2*J ) = ITMP
                  END IF
               END IF
 60         CONTINUE
         END IF
      ENDIF
*
*
      WORK( 1 ) = LWMIN
      IWORK( 1 ) = LIWMIN
      RETURN
*
*     End of DSTEMR
*
      END
