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659 lines
22 KiB
C
659 lines
22 KiB
C
/* ssyevr.f -- translated by f2c (version 20061008).
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You must link the resulting object file with libf2c:
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on Microsoft Windows system, link with libf2c.lib;
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on Linux or Unix systems, link with .../path/to/libf2c.a -lm
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or, if you install libf2c.a in a standard place, with -lf2c -lm
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-- in that order, at the end of the command line, as in
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cc *.o -lf2c -lm
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
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http://www.netlib.org/f2c/libf2c.zip
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*/
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#include "clapack.h"
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/* Table of constant values */
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static integer c__10 = 10;
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static integer c__1 = 1;
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static integer c__2 = 2;
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static integer c__3 = 3;
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static integer c__4 = 4;
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static integer c_n1 = -1;
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/* Subroutine */ int ssyevr_(char *jobz, char *range, char *uplo, integer *n,
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real *a, integer *lda, real *vl, real *vu, integer *il, integer *iu,
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real *abstol, integer *m, real *w, real *z__, integer *ldz, integer *
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isuppz, real *work, integer *lwork, integer *iwork, integer *liwork,
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integer *info)
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{
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/* System generated locals */
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integer a_dim1, a_offset, z_dim1, z_offset, i__1, i__2;
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real r__1, r__2;
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/* Builtin functions */
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double sqrt(doublereal);
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/* Local variables */
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integer i__, j, nb, jj;
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real eps, vll, vuu, tmp1;
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integer indd, inde;
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real anrm;
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integer imax;
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real rmin, rmax;
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logical test;
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integer inddd, indee;
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real sigma;
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extern logical lsame_(char *, char *);
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integer iinfo;
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extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *);
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char order[1];
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integer indwk, lwmin;
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logical lower;
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extern /* Subroutine */ int scopy_(integer *, real *, integer *, real *,
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integer *), sswap_(integer *, real *, integer *, real *, integer *
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);
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logical wantz, alleig, indeig;
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integer iscale, ieeeok, indibl, indifl;
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logical valeig;
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extern doublereal slamch_(char *);
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real safmin;
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extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
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integer *, integer *);
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extern /* Subroutine */ int xerbla_(char *, integer *);
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real abstll, bignum;
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integer indtau, indisp, indiwo, indwkn, liwmin;
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logical tryrac;
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extern /* Subroutine */ int sstein_(integer *, real *, real *, integer *,
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real *, integer *, integer *, real *, integer *, real *, integer *
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, integer *, integer *), ssterf_(integer *, real *, real *,
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integer *);
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integer llwrkn, llwork, nsplit;
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real smlnum;
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extern doublereal slansy_(char *, char *, integer *, real *, integer *,
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real *);
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extern /* Subroutine */ int sstebz_(char *, char *, integer *, real *,
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real *, integer *, integer *, real *, real *, real *, integer *,
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integer *, real *, integer *, integer *, real *, integer *,
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integer *), sstemr_(char *, char *, integer *,
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real *, real *, real *, real *, integer *, integer *, integer *,
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real *, real *, integer *, integer *, integer *, logical *, real *
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, integer *, integer *, integer *, integer *);
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integer lwkopt;
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logical lquery;
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extern /* Subroutine */ int sormtr_(char *, char *, char *, integer *,
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integer *, real *, integer *, real *, real *, integer *, real *,
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integer *, integer *), ssytrd_(char *,
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integer *, real *, integer *, real *, real *, real *, real *,
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integer *, integer *);
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/* -- LAPACK driver routine (version 3.2) -- */
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/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
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/* November 2006 */
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/* .. Scalar Arguments .. */
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/* .. */
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/* .. Array Arguments .. */
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/* .. */
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/* Purpose */
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/* ======= */
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/* SSYEVR computes selected eigenvalues and, optionally, eigenvectors */
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/* of a real symmetric matrix A. Eigenvalues and eigenvectors can be */
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/* selected by specifying either a range of values or a range of */
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/* indices for the desired eigenvalues. */
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/* SSYEVR first reduces the matrix A to tridiagonal form T with a call */
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/* to SSYTRD. Then, whenever possible, SSYEVR calls SSTEMR to compute */
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/* the eigenspectrum using Relatively Robust Representations. SSTEMR */
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/* computes eigenvalues by the dqds algorithm, while orthogonal */
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/* eigenvectors are computed from various "good" L D L^T representations */
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/* (also known as Relatively Robust Representations). Gram-Schmidt */
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/* orthogonalization is avoided as far as possible. More specifically, */
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/* the various steps of the algorithm are as follows. */
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/* For each unreduced block (submatrix) of T, */
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/* (a) Compute T - sigma I = L D L^T, so that L and D */
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/* define all the wanted eigenvalues to high relative accuracy. */
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/* This means that small relative changes in the entries of D and L */
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/* cause only small relative changes in the eigenvalues and */
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/* eigenvectors. The standard (unfactored) representation of the */
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/* tridiagonal matrix T does not have this property in general. */
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/* (b) Compute the eigenvalues to suitable accuracy. */
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/* If the eigenvectors are desired, the algorithm attains full */
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/* accuracy of the computed eigenvalues only right before */
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/* the corresponding vectors have to be computed, see steps c) and d). */
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/* (c) For each cluster of close eigenvalues, select a new */
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/* shift close to the cluster, find a new factorization, and refine */
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/* the shifted eigenvalues to suitable accuracy. */
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/* (d) For each eigenvalue with a large enough relative separation compute */
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/* the corresponding eigenvector by forming a rank revealing twisted */
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/* factorization. Go back to (c) for any clusters that remain. */
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/* The desired accuracy of the output can be specified by the input */
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/* parameter ABSTOL. */
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/* For more details, see SSTEMR's documentation and: */
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/* - Inderjit S. Dhillon and Beresford N. Parlett: "Multiple representations */
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/* to compute orthogonal eigenvectors of symmetric tridiagonal matrices," */
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/* Linear Algebra and its Applications, 387(1), pp. 1-28, August 2004. */
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/* - Inderjit Dhillon and Beresford Parlett: "Orthogonal Eigenvectors and */
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/* Relative Gaps," SIAM Journal on Matrix Analysis and Applications, Vol. 25, */
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/* 2004. Also LAPACK Working Note 154. */
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/* - Inderjit Dhillon: "A new O(n^2) algorithm for the symmetric */
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/* tridiagonal eigenvalue/eigenvector problem", */
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/* Computer Science Division Technical Report No. UCB/CSD-97-971, */
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/* UC Berkeley, May 1997. */
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/* Note 1 : SSYEVR calls SSTEMR when the full spectrum is requested */
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/* on machines which conform to the ieee-754 floating point standard. */
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/* SSYEVR calls SSTEBZ and SSTEIN on non-ieee machines and */
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/* when partial spectrum requests are made. */
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/* Normal execution of SSTEMR may create NaNs and infinities and */
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/* hence may abort due to a floating point exception in environments */
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/* which do not handle NaNs and infinities in the ieee standard default */
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/* manner. */
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/* Arguments */
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/* ========= */
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/* JOBZ (input) CHARACTER*1 */
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/* = 'N': Compute eigenvalues only; */
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/* = 'V': Compute eigenvalues and eigenvectors. */
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/* RANGE (input) CHARACTER*1 */
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/* = 'A': all eigenvalues will be found. */
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/* = 'V': all eigenvalues in the half-open interval (VL,VU] */
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/* will be found. */
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/* = 'I': the IL-th through IU-th eigenvalues will be found. */
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/* ********* For RANGE = 'V' or 'I' and IU - IL < N - 1, SSTEBZ and */
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/* ********* SSTEIN are called */
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/* UPLO (input) CHARACTER*1 */
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/* = 'U': Upper triangle of A is stored; */
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/* = 'L': Lower triangle of A is stored. */
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/* N (input) INTEGER */
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/* The order of the matrix A. N >= 0. */
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/* A (input/output) REAL array, dimension (LDA, N) */
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/* On entry, the symmetric matrix A. If UPLO = 'U', the */
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/* leading N-by-N upper triangular part of A contains the */
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/* upper triangular part of the matrix A. If UPLO = 'L', */
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/* the leading N-by-N lower triangular part of A contains */
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/* the lower triangular part of the matrix A. */
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/* On exit, the lower triangle (if UPLO='L') or the upper */
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/* triangle (if UPLO='U') of A, including the diagonal, is */
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/* destroyed. */
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/* LDA (input) INTEGER */
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/* The leading dimension of the array A. LDA >= max(1,N). */
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/* VL (input) REAL */
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/* VU (input) REAL */
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/* If RANGE='V', the lower and upper bounds of the interval to */
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/* be searched for eigenvalues. VL < VU. */
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/* Not referenced if RANGE = 'A' or 'I'. */
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/* IL (input) INTEGER */
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/* IU (input) INTEGER */
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/* If RANGE='I', the indices (in ascending order) of the */
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/* smallest and largest eigenvalues to be returned. */
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/* 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. */
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/* Not referenced if RANGE = 'A' or 'V'. */
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/* ABSTOL (input) REAL */
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/* The absolute error tolerance for the eigenvalues. */
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/* An approximate eigenvalue is accepted as converged */
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/* when it is determined to lie in an interval [a,b] */
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/* of width less than or equal to */
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/* ABSTOL + EPS * max( |a|,|b| ) , */
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/* where EPS is the machine precision. If ABSTOL is less than */
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/* or equal to zero, then EPS*|T| will be used in its place, */
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/* where |T| is the 1-norm of the tridiagonal matrix obtained */
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/* by reducing A to tridiagonal form. */
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/* See "Computing Small Singular Values of Bidiagonal Matrices */
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/* with Guaranteed High Relative Accuracy," by Demmel and */
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/* Kahan, LAPACK Working Note #3. */
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/* If high relative accuracy is important, set ABSTOL to */
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/* SLAMCH( 'Safe minimum' ). Doing so will guarantee that */
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/* eigenvalues are computed to high relative accuracy when */
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/* possible in future releases. The current code does not */
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/* make any guarantees about high relative accuracy, but */
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/* future releases will. See J. Barlow and J. Demmel, */
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/* "Computing Accurate Eigensystems of Scaled Diagonally */
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/* Dominant Matrices", LAPACK Working Note #7, for a discussion */
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/* of which matrices define their eigenvalues to high relative */
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/* accuracy. */
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/* M (output) INTEGER */
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/* The total number of eigenvalues found. 0 <= M <= N. */
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/* If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1. */
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/* W (output) REAL array, dimension (N) */
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/* The first M elements contain the selected eigenvalues in */
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/* ascending order. */
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/* Z (output) REAL array, dimension (LDZ, max(1,M)) */
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/* If JOBZ = 'V', then if INFO = 0, the first M columns of Z */
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/* contain the orthonormal eigenvectors of the matrix A */
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/* corresponding to the selected eigenvalues, with the i-th */
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/* column of Z holding the eigenvector associated with W(i). */
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/* If JOBZ = 'N', then Z is not referenced. */
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/* Note: the user must ensure that at least max(1,M) columns are */
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/* supplied in the array Z; if RANGE = 'V', the exact value of M */
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/* is not known in advance and an upper bound must be used. */
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/* Supplying N columns is always safe. */
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/* LDZ (input) INTEGER */
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/* The leading dimension of the array Z. LDZ >= 1, and if */
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/* JOBZ = 'V', LDZ >= max(1,N). */
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/* ISUPPZ (output) INTEGER array, dimension ( 2*max(1,M) ) */
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/* The support of the eigenvectors in Z, i.e., the indices */
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/* indicating the nonzero elements in Z. The i-th eigenvector */
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/* is nonzero only in elements ISUPPZ( 2*i-1 ) through */
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/* ISUPPZ( 2*i ). */
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/* ********* Implemented only for RANGE = 'A' or 'I' and IU - IL = N - 1 */
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/* WORK (workspace/output) REAL array, dimension (MAX(1,LWORK)) */
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/* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */
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/* LWORK (input) INTEGER */
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/* The dimension of the array WORK. LWORK >= max(1,26*N). */
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/* For optimal efficiency, LWORK >= (NB+6)*N, */
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/* where NB is the max of the blocksize for SSYTRD and SORMTR */
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/* returned by ILAENV. */
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/* If LWORK = -1, then a workspace query is assumed; the routine */
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/* only calculates the optimal sizes of the WORK and IWORK */
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/* arrays, returns these values as the first entries of the WORK */
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/* and IWORK arrays, and no error message related to LWORK or */
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/* LIWORK is issued by XERBLA. */
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/* IWORK (workspace/output) INTEGER array, dimension (MAX(1,LIWORK)) */
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/* On exit, if INFO = 0, IWORK(1) returns the optimal LWORK. */
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/* LIWORK (input) INTEGER */
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/* The dimension of the array IWORK. LIWORK >= max(1,10*N). */
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/* If LIWORK = -1, then a workspace query is assumed; the */
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/* routine only calculates the optimal sizes of the WORK and */
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/* IWORK arrays, returns these values as the first entries of */
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/* the WORK and IWORK arrays, and no error message related to */
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/* LWORK or LIWORK is issued by XERBLA. */
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/* INFO (output) INTEGER */
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/* = 0: successful exit */
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/* < 0: if INFO = -i, the i-th argument had an illegal value */
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/* > 0: Internal error */
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/* Further Details */
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/* =============== */
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/* Based on contributions by */
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/* Inderjit Dhillon, IBM Almaden, USA */
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/* Osni Marques, LBNL/NERSC, USA */
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/* Ken Stanley, Computer Science Division, University of */
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/* California at Berkeley, USA */
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/* Jason Riedy, Computer Science Division, University of */
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/* California at Berkeley, USA */
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/* ===================================================================== */
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/* .. Parameters .. */
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/* .. */
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/* .. Local Scalars .. */
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/* .. */
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/* .. External Functions .. */
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/* .. */
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/* .. External Subroutines .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. Executable Statements .. */
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/* Test the input parameters. */
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/* Parameter adjustments */
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a_dim1 = *lda;
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a_offset = 1 + a_dim1;
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a -= a_offset;
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--w;
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z_dim1 = *ldz;
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z_offset = 1 + z_dim1;
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z__ -= z_offset;
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--isuppz;
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--work;
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--iwork;
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/* Function Body */
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ieeeok = ilaenv_(&c__10, "SSYEVR", "N", &c__1, &c__2, &c__3, &c__4);
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lower = lsame_(uplo, "L");
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wantz = lsame_(jobz, "V");
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alleig = lsame_(range, "A");
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valeig = lsame_(range, "V");
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indeig = lsame_(range, "I");
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lquery = *lwork == -1 || *liwork == -1;
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/* Computing MAX */
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i__1 = 1, i__2 = *n * 26;
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lwmin = max(i__1,i__2);
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/* Computing MAX */
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i__1 = 1, i__2 = *n * 10;
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liwmin = max(i__1,i__2);
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*info = 0;
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if (! (wantz || lsame_(jobz, "N"))) {
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*info = -1;
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} else if (! (alleig || valeig || indeig)) {
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*info = -2;
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} else if (! (lower || lsame_(uplo, "U"))) {
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*info = -3;
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} else if (*n < 0) {
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*info = -4;
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} else if (*lda < max(1,*n)) {
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*info = -6;
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} else {
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if (valeig) {
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if (*n > 0 && *vu <= *vl) {
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*info = -8;
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}
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} else if (indeig) {
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if (*il < 1 || *il > max(1,*n)) {
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*info = -9;
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} else if (*iu < min(*n,*il) || *iu > *n) {
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*info = -10;
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}
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}
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}
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if (*info == 0) {
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if (*ldz < 1 || wantz && *ldz < *n) {
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*info = -15;
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}
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}
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if (*info == 0) {
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nb = ilaenv_(&c__1, "SSYTRD", uplo, n, &c_n1, &c_n1, &c_n1);
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/* Computing MAX */
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i__1 = nb, i__2 = ilaenv_(&c__1, "SORMTR", uplo, n, &c_n1, &c_n1, &
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c_n1);
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nb = max(i__1,i__2);
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/* Computing MAX */
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i__1 = (nb + 1) * *n;
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lwkopt = max(i__1,lwmin);
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work[1] = (real) lwkopt;
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iwork[1] = liwmin;
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if (*lwork < lwmin && ! lquery) {
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*info = -18;
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} else if (*liwork < liwmin && ! lquery) {
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*info = -20;
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}
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_("SSYEVR", &i__1);
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return 0;
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} else if (lquery) {
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return 0;
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}
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/* Quick return if possible */
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*m = 0;
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if (*n == 0) {
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work[1] = 1.f;
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return 0;
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}
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if (*n == 1) {
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work[1] = 26.f;
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if (alleig || indeig) {
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*m = 1;
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w[1] = a[a_dim1 + 1];
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} else {
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if (*vl < a[a_dim1 + 1] && *vu >= a[a_dim1 + 1]) {
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*m = 1;
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w[1] = a[a_dim1 + 1];
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}
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}
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if (wantz) {
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z__[z_dim1 + 1] = 1.f;
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}
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return 0;
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}
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/* Get machine constants. */
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safmin = slamch_("Safe minimum");
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eps = slamch_("Precision");
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smlnum = safmin / eps;
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bignum = 1.f / smlnum;
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rmin = sqrt(smlnum);
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/* Computing MIN */
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r__1 = sqrt(bignum), r__2 = 1.f / sqrt(sqrt(safmin));
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rmax = dmin(r__1,r__2);
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/* Scale matrix to allowable range, if necessary. */
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iscale = 0;
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abstll = *abstol;
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if (valeig) {
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vll = *vl;
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vuu = *vu;
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}
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anrm = slansy_("M", uplo, n, &a[a_offset], lda, &work[1]);
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if (anrm > 0.f && anrm < rmin) {
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iscale = 1;
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sigma = rmin / anrm;
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} else if (anrm > rmax) {
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iscale = 1;
|
|
sigma = rmax / anrm;
|
|
}
|
|
if (iscale == 1) {
|
|
if (lower) {
|
|
i__1 = *n;
|
|
for (j = 1; j <= i__1; ++j) {
|
|
i__2 = *n - j + 1;
|
|
sscal_(&i__2, &sigma, &a[j + j * a_dim1], &c__1);
|
|
/* L10: */
|
|
}
|
|
} else {
|
|
i__1 = *n;
|
|
for (j = 1; j <= i__1; ++j) {
|
|
sscal_(&j, &sigma, &a[j * a_dim1 + 1], &c__1);
|
|
/* L20: */
|
|
}
|
|
}
|
|
if (*abstol > 0.f) {
|
|
abstll = *abstol * sigma;
|
|
}
|
|
if (valeig) {
|
|
vll = *vl * sigma;
|
|
vuu = *vu * sigma;
|
|
}
|
|
}
|
|
/* Initialize indices into workspaces. Note: The IWORK indices are */
|
|
/* used only if SSTERF or SSTEMR fail. */
|
|
/* WORK(INDTAU:INDTAU+N-1) stores the scalar factors of the */
|
|
/* elementary reflectors used in SSYTRD. */
|
|
indtau = 1;
|
|
/* WORK(INDD:INDD+N-1) stores the tridiagonal's diagonal entries. */
|
|
indd = indtau + *n;
|
|
/* WORK(INDE:INDE+N-1) stores the off-diagonal entries of the */
|
|
/* tridiagonal matrix from SSYTRD. */
|
|
inde = indd + *n;
|
|
/* WORK(INDDD:INDDD+N-1) is a copy of the diagonal entries over */
|
|
/* -written by SSTEMR (the SSTERF path copies the diagonal to W). */
|
|
inddd = inde + *n;
|
|
/* WORK(INDEE:INDEE+N-1) is a copy of the off-diagonal entries over */
|
|
/* -written while computing the eigenvalues in SSTERF and SSTEMR. */
|
|
indee = inddd + *n;
|
|
/* INDWK is the starting offset of the left-over workspace, and */
|
|
/* LLWORK is the remaining workspace size. */
|
|
indwk = indee + *n;
|
|
llwork = *lwork - indwk + 1;
|
|
/* IWORK(INDIBL:INDIBL+M-1) corresponds to IBLOCK in SSTEBZ and */
|
|
/* stores the block indices of each of the M<=N eigenvalues. */
|
|
indibl = 1;
|
|
/* IWORK(INDISP:INDISP+NSPLIT-1) corresponds to ISPLIT in SSTEBZ and */
|
|
/* stores the starting and finishing indices of each block. */
|
|
indisp = indibl + *n;
|
|
/* IWORK(INDIFL:INDIFL+N-1) stores the indices of eigenvectors */
|
|
/* that corresponding to eigenvectors that fail to converge in */
|
|
/* SSTEIN. This information is discarded; if any fail, the driver */
|
|
/* returns INFO > 0. */
|
|
indifl = indisp + *n;
|
|
/* INDIWO is the offset of the remaining integer workspace. */
|
|
indiwo = indisp + *n;
|
|
|
|
/* Call SSYTRD to reduce symmetric matrix to tridiagonal form. */
|
|
|
|
ssytrd_(uplo, n, &a[a_offset], lda, &work[indd], &work[inde], &work[
|
|
indtau], &work[indwk], &llwork, &iinfo);
|
|
|
|
/* If all eigenvalues are desired */
|
|
/* then call SSTERF or SSTEMR and SORMTR. */
|
|
|
|
test = FALSE_;
|
|
if (indeig) {
|
|
if (*il == 1 && *iu == *n) {
|
|
test = TRUE_;
|
|
}
|
|
}
|
|
if ((alleig || test) && ieeeok == 1) {
|
|
if (! wantz) {
|
|
scopy_(n, &work[indd], &c__1, &w[1], &c__1);
|
|
i__1 = *n - 1;
|
|
scopy_(&i__1, &work[inde], &c__1, &work[indee], &c__1);
|
|
ssterf_(n, &w[1], &work[indee], info);
|
|
} else {
|
|
i__1 = *n - 1;
|
|
scopy_(&i__1, &work[inde], &c__1, &work[indee], &c__1);
|
|
scopy_(n, &work[indd], &c__1, &work[inddd], &c__1);
|
|
|
|
if (*abstol <= *n * 2.f * eps) {
|
|
tryrac = TRUE_;
|
|
} else {
|
|
tryrac = FALSE_;
|
|
}
|
|
sstemr_(jobz, "A", n, &work[inddd], &work[indee], vl, vu, il, iu,
|
|
m, &w[1], &z__[z_offset], ldz, n, &isuppz[1], &tryrac, &
|
|
work[indwk], lwork, &iwork[1], liwork, info);
|
|
|
|
|
|
|
|
/* Apply orthogonal matrix used in reduction to tridiagonal */
|
|
/* form to eigenvectors returned by SSTEIN. */
|
|
|
|
if (wantz && *info == 0) {
|
|
indwkn = inde;
|
|
llwrkn = *lwork - indwkn + 1;
|
|
sormtr_("L", uplo, "N", n, m, &a[a_offset], lda, &work[indtau]
|
|
, &z__[z_offset], ldz, &work[indwkn], &llwrkn, &iinfo);
|
|
}
|
|
}
|
|
|
|
|
|
if (*info == 0) {
|
|
/* Everything worked. Skip SSTEBZ/SSTEIN. IWORK(:) are */
|
|
/* undefined. */
|
|
*m = *n;
|
|
goto L30;
|
|
}
|
|
*info = 0;
|
|
}
|
|
|
|
/* Otherwise, call SSTEBZ and, if eigenvectors are desired, SSTEIN. */
|
|
/* Also call SSTEBZ and SSTEIN if SSTEMR fails. */
|
|
|
|
if (wantz) {
|
|
*(unsigned char *)order = 'B';
|
|
} else {
|
|
*(unsigned char *)order = 'E';
|
|
}
|
|
sstebz_(range, order, n, &vll, &vuu, il, iu, &abstll, &work[indd], &work[
|
|
inde], m, &nsplit, &w[1], &iwork[indibl], &iwork[indisp], &work[
|
|
indwk], &iwork[indiwo], info);
|
|
|
|
if (wantz) {
|
|
sstein_(n, &work[indd], &work[inde], m, &w[1], &iwork[indibl], &iwork[
|
|
indisp], &z__[z_offset], ldz, &work[indwk], &iwork[indiwo], &
|
|
iwork[indifl], info);
|
|
|
|
/* Apply orthogonal matrix used in reduction to tridiagonal */
|
|
/* form to eigenvectors returned by SSTEIN. */
|
|
|
|
indwkn = inde;
|
|
llwrkn = *lwork - indwkn + 1;
|
|
sormtr_("L", uplo, "N", n, m, &a[a_offset], lda, &work[indtau], &z__[
|
|
z_offset], ldz, &work[indwkn], &llwrkn, &iinfo);
|
|
}
|
|
|
|
/* If matrix was scaled, then rescale eigenvalues appropriately. */
|
|
|
|
/* Jump here if SSTEMR/SSTEIN succeeded. */
|
|
L30:
|
|
if (iscale == 1) {
|
|
if (*info == 0) {
|
|
imax = *m;
|
|
} else {
|
|
imax = *info - 1;
|
|
}
|
|
r__1 = 1.f / sigma;
|
|
sscal_(&imax, &r__1, &w[1], &c__1);
|
|
}
|
|
|
|
/* If eigenvalues are not in order, then sort them, along with */
|
|
/* eigenvectors. Note: We do not sort the IFAIL portion of IWORK. */
|
|
/* It may not be initialized (if SSTEMR/SSTEIN succeeded), and we do */
|
|
/* not return this detailed information to the user. */
|
|
|
|
if (wantz) {
|
|
i__1 = *m - 1;
|
|
for (j = 1; j <= i__1; ++j) {
|
|
i__ = 0;
|
|
tmp1 = w[j];
|
|
i__2 = *m;
|
|
for (jj = j + 1; jj <= i__2; ++jj) {
|
|
if (w[jj] < tmp1) {
|
|
i__ = jj;
|
|
tmp1 = w[jj];
|
|
}
|
|
/* L40: */
|
|
}
|
|
|
|
if (i__ != 0) {
|
|
w[i__] = w[j];
|
|
w[j] = tmp1;
|
|
sswap_(n, &z__[i__ * z_dim1 + 1], &c__1, &z__[j * z_dim1 + 1],
|
|
&c__1);
|
|
}
|
|
/* L50: */
|
|
}
|
|
}
|
|
|
|
/* Set WORK(1) to optimal workspace size. */
|
|
|
|
work[1] = (real) lwkopt;
|
|
iwork[1] = liwmin;
|
|
|
|
return 0;
|
|
|
|
/* End of SSYEVR */
|
|
|
|
} /* ssyevr_ */
|