text: /* ../netlib/sstegr.f -- translated by f2c (version 20100827). You must link the resulting object file with libf2c: on Microsoft Windows system, link with libf2c.lib;
   on Linux or Unix systems, link with .../path/to/libf2c.a -lm or, if you install libf2c.a in a standard place, with -lf2c -lm -- in that order, at the end of the command line, as in cc *.o -lf2c -lm Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., http://www.netlib.org/f2c/libf2c.zip */
  #include "FLA_f2c.h" /* > \brief \b SSTEGR */
  /* =========== DOCUMENTATION =========== */
  /* Online html documentation available at */
  /* http://www.netlib.org/lapack/explore-html/ */
  /* > \htmlonly */
  /* > Download SSTEGR + dependencies */
  /* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/sstegr. f"> */
  /* > [TGZ]</a> */
  /* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/sstegr. f"> */
  /* > [ZIP]</a> */
  /* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/sstegr. f"> */
  /* > [TXT]</a> */
  /* > \endhtmlonly */
  /* Definition: */
  /* =========== */
  /* SUBROUTINE SSTEGR( JOBZ, RANGE, N, D, E, VL, VU, IL, IU, */
  /* ABSTOL, M, W, Z, LDZ, ISUPPZ, WORK, LWORK, IWORK, */
  /* LIWORK, INFO ) */
  /* .. Scalar Arguments .. */
  /* CHARACTER JOBZ, RANGE */
  /* INTEGER IL, INFO, IU, LDZ, LIWORK, LWORK, M, N */
  /* REAL ABSTOL, VL, VU */
  /* .. */
  /* .. Array Arguments .. */
  /* INTEGER ISUPPZ( * ), IWORK( * ) */
  /* REAL D( * ), E( * ), W( * ), WORK( * ) */
  /* REAL Z( LDZ, * ) */
  /* .. */
  /* > \par Purpose: */
  /* ============= */
  /* > */
  /* > \verbatim */
  /* > */
  /* > SSTEGR 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. */
  /* > */
  /* > SSTEGR is a compatability wrapper around the improved SSTEMR routine. */
  /* > See SSTEMR for further details. */
  /* > */
  /* > One important change is that the ABSTOL parameter no longer provides any */
  /* > benefit and hence is no longer used. */
  /* > */
  /* > Note : SSTEGR and SSTEMR work only on machines which follow */
  /* > IEEE-754 floating-point standard in their handling of infinities and */
  /* > NaNs. Normal execution may create these exceptiona values and hence */
  /* > may abort due to a floating point exception in environments which */
  /* > do not conform to the IEEE-754 standard. */
  /* > \endverbatim */
  /* Arguments: */
  /* ========== */
  /* > \param[in] JOBZ */
  /* > \verbatim */
  /* > JOBZ is CHARACTER*1 */
  /* > = 'N': Compute eigenvalues only;
  */
  /* > = 'V': Compute eigenvalues and eigenvectors. */
  /* > \endverbatim */
  /* > */
  /* > \param[in] RANGE */
  /* > \verbatim */
  /* > RANGE is 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. */
  /* > \endverbatim */
  /* > */
  /* > \param[in] N */
  /* > \verbatim */
  /* > N is INTEGER */
  /* > The order of the matrix. N >= 0. */
  /* > \endverbatim */
  /* > */
  /* > \param[in,out] D */
  /* > \verbatim */
  /* > D is REAL array, dimension (N) */
  /* > On entry, the N diagonal elements of the tridiagonal matrix */
  /* > T. On exit, D is overwritten. */
  /* > \endverbatim */
  /* > */
  /* > \param[in,out] E */
  /* > \verbatim */
  /* > E is REAL 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. */
  /* > \endverbatim */
  /* > */
  /* > \param[in] VL */
  /* > \verbatim */
  /* > VL is REAL */
  /* > \endverbatim */
  /* > */
  /* > \param[in] VU */
  /* > \verbatim */
  /* > VU is REAL */
  /* > */
  /* > 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'. */
  /* > \endverbatim */
  /* > */
  /* > \param[in] IL */
  /* > \verbatim */
  /* > IL is INTEGER */
  /* > \endverbatim */
  /* > */
  /* > \param[in] IU */
  /* > \verbatim */
  /* > IU is 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'. */
  /* > \endverbatim */
  /* > */
  /* > \param[in] ABSTOL */
  /* > \verbatim */
  /* > ABSTOL is REAL */
  /* > Unused. Was the absolute error tolerance for the */
  /* > eigenvalues/eigenvectors in previous versions. */
  /* > \endverbatim */
  /* > */
  /* > \param[out] M */
  /* > \verbatim */
  /* > M is INTEGER */
  /* > The total number of eigenvalues found. 0 <= M <= N. */
  /* > If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1. */
  /* > \endverbatim */
  /* > */
  /* > \param[out] W */
  /* > \verbatim */
  /* > W is REAL array, dimension (N) */
  /* > The first M elements contain the selected eigenvalues in */
  /* > ascending order. */
  /* > \endverbatim */
  /* > */
  /* > \param[out] Z */
  /* > \verbatim */
  /* > Z is REAL 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 an upper bound must be used. */
  /* > Supplying N columns is always safe. */
  /* > \endverbatim */
  /* > */
  /* > \param[in] LDZ */
  /* > \verbatim */
  /* > LDZ is INTEGER */
  /* > The leading dimension of the array Z. LDZ >= 1, and if */
  /* > JOBZ = 'V', then LDZ >= max(1,N). */
  /* > \endverbatim */
  /* > */
  /* > \param[out] ISUPPZ */
  /* > \verbatim */
  /* > ISUPPZ is 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. */
  /* > \endverbatim */
  /* > */
  /* > \param[out] WORK */
  /* > \verbatim */
  /* > WORK is REAL array, dimension (LWORK) */
  /* > On exit, if INFO = 0, WORK(1) returns the optimal */
  /* > (and minimal) LWORK. */
  /* > \endverbatim */
  /* > */
  /* > \param[in] LWORK */
  /* > \verbatim */
  /* > LWORK is 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. */
  /* > \endverbatim */
  /* > */
  /* > \param[out] IWORK */
  /* > \verbatim */
  /* > IWORK is INTEGER array, dimension (LIWORK) */
  /* > On exit, if INFO = 0, IWORK(1) returns the optimal LIWORK. */
  /* > \endverbatim */
  /* > */
  /* > \param[in] LIWORK */
  /* > \verbatim */
  /* > LIWORK is 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. */
  /* > \endverbatim */
  /* > */
  /* > \param[out] INFO */
  /* > \verbatim */
  /* > INFO is 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 SLARRE, */
  /* > if INFO = 2X, internal error in SLARRV. */
  /* > Here, the digit X = ABS( IINFO ) < 10, where IINFO is */
  /* > the nonzero error code returned by SLARRE or */
  /* > SLARRV, respectively. */
  /* > \endverbatim */
  /* Authors: */
  /* ======== */
  /* > \author Univ. of Tennessee */
  /* > \author Univ. of California Berkeley */
  /* > \author Univ. of Colorado Denver */
  /* > \author NAG Ltd. */
  /* > \date November 2011 */
  /* > \ingroup realOTHERcomputational */
  /* > \par Contributors: */
  /* ================== */
  /* > */
  /* > Inderjit Dhillon, IBM Almaden, USA \n */
  /* > Osni Marques, LBNL/NERSC, USA \n */
  /* > Christof Voemel, LBNL/NERSC, USA \n */
  /* ===================================================================== */
  /* Subroutine */
  int sstegr_(char *jobz, char *range, integer *n, real *d__, real *e, real *vl, real *vu, integer *il, integer *iu, real *abstol, integer *m, real *w, real *z__, integer *ldz, integer *isuppz, real * work, integer *lwork, integer *iwork, integer *liwork, integer *info)
  {
      /* System generated locals */
      integer z_dim1, z_offset;
      /* Local variables */
      logical tryrac;
      extern /* Subroutine */
      int sstemr_(char *, char *, integer *, real *, real *, real *, real *, integer *, integer *, integer *, real *, real *, integer *, integer *, integer *, logical *, real *, integer *, integer *, integer *, integer *);
      /* -- LAPACK computational routine (version 3.4.0) -- */
      /* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
      /* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
      /* November 2011 */
      /* .. Scalar Arguments .. */
      /* .. */
      /* .. Array Arguments .. */
      /* .. */
      /* ===================================================================== */
      /* .. Local Scalars .. */
      /* .. */
      /* .. External Subroutines .. */
      /* .. */
      /* .. Executable Statements .. */
      /* Parameter adjustments */
      --d__;
      --e;
      --w;
      z_dim1 = *ldz;
      z_offset = 1 + z_dim1;
      z__ -= z_offset;
      --isuppz;
      --work;
      --iwork;
      /* Function Body */
      *info = 0;
      tryrac = FALSE_;
      sstemr_(jobz, range, n, &d__[1], &e[1], vl, vu, il, iu, m, &w[1], &z__[ z_offset], ldz, n, &isuppz[1], &tryrac, &work[1], lwork, &iwork[1] , liwork, info);
      /* End of SSTEGR */
      return 0;
  }
  /* sstegr_ */
  