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793 lines
26 KiB
793 lines
26 KiB
/* dlarrd.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__1 = 1; |
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static integer c_n1 = -1; |
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static integer c__3 = 3; |
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static integer c__2 = 2; |
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static integer c__0 = 0; |
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/* Subroutine */ int dlarrd_(char *range, char *order, integer *n, doublereal |
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*vl, doublereal *vu, integer *il, integer *iu, doublereal *gers, |
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doublereal *reltol, doublereal *d__, doublereal *e, doublereal *e2, |
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doublereal *pivmin, integer *nsplit, integer *isplit, integer *m, |
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doublereal *w, doublereal *werr, doublereal *wl, doublereal *wu, |
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integer *iblock, integer *indexw, doublereal *work, integer *iwork, |
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integer *info) |
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{ |
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/* System generated locals */ |
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integer i__1, i__2, i__3; |
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doublereal d__1, d__2; |
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/* Builtin functions */ |
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double log(doublereal); |
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/* Local variables */ |
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integer i__, j, ib, ie, je, nb; |
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doublereal gl; |
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integer im, in; |
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doublereal gu; |
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integer iw, jee; |
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doublereal eps; |
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integer nwl; |
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doublereal wlu, wul; |
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integer nwu; |
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doublereal tmp1, tmp2; |
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integer iend, jblk, ioff, iout, itmp1, itmp2, jdisc; |
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extern logical lsame_(char *, char *); |
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integer iinfo; |
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doublereal atoli; |
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integer iwoff, itmax; |
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doublereal wkill, rtoli, uflow, tnorm; |
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extern doublereal dlamch_(char *); |
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integer ibegin; |
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extern /* Subroutine */ int dlaebz_(integer *, integer *, integer *, |
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integer *, integer *, integer *, doublereal *, doublereal *, |
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doublereal *, doublereal *, doublereal *, doublereal *, integer *, |
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doublereal *, doublereal *, integer *, integer *, doublereal *, |
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integer *, integer *); |
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integer irange, idiscl, idumma[1]; |
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extern integer ilaenv_(integer *, char *, char *, integer *, integer *, |
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integer *, integer *); |
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integer idiscu; |
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logical ncnvrg, toofew; |
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/* -- LAPACK auxiliary routine (version 3.2.1) -- */ |
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/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */ |
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/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */ |
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/* -- April 2009 -- */ |
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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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/* DLARRD computes the eigenvalues of a symmetric tridiagonal */ |
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/* matrix T to suitable accuracy. This is an auxiliary code to be */ |
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/* called from DSTEMR. */ |
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/* The user may ask for all eigenvalues, all eigenvalues */ |
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/* in the half-open interval (VL, VU], or the IL-th through IU-th */ |
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/* eigenvalues. */ |
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/* To avoid overflow, the matrix must be scaled so that its */ |
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/* largest element is no greater than overflow**(1/2) * */ |
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/* underflow**(1/4) in absolute value, and for greatest */ |
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/* accuracy, it should not be much smaller than that. */ |
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/* See W. Kahan "Accurate Eigenvalues of a Symmetric Tridiagonal */ |
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/* Matrix", Report CS41, Computer Science Dept., Stanford */ |
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/* University, July 21, 1966. */ |
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/* Arguments */ |
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/* ========= */ |
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/* RANGE (input) CHARACTER */ |
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/* = 'A': ("All") all eigenvalues will be found. */ |
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/* = 'V': ("Value") all eigenvalues in the half-open interval */ |
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/* (VL, VU] will be found. */ |
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/* = 'I': ("Index") the IL-th through IU-th eigenvalues (of the */ |
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/* entire matrix) will be found. */ |
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/* ORDER (input) CHARACTER */ |
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/* = 'B': ("By Block") the eigenvalues will be grouped by */ |
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/* split-off block (see IBLOCK, ISPLIT) and */ |
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/* ordered from smallest to largest within */ |
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/* the block. */ |
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/* = 'E': ("Entire matrix") */ |
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/* the eigenvalues for the entire matrix */ |
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/* will be ordered from smallest to */ |
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/* largest. */ |
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/* N (input) INTEGER */ |
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/* The order of the tridiagonal matrix T. N >= 0. */ |
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/* VL (input) DOUBLE PRECISION */ |
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/* VU (input) DOUBLE PRECISION */ |
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/* If RANGE='V', the lower and upper bounds of the interval to */ |
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/* be searched for eigenvalues. Eigenvalues less than or equal */ |
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/* to VL, or greater than VU, will not be returned. 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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/* GERS (input) DOUBLE PRECISION array, dimension (2*N) */ |
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/* The N Gerschgorin intervals (the i-th Gerschgorin interval */ |
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/* is (GERS(2*i-1), GERS(2*i)). */ |
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/* RELTOL (input) DOUBLE PRECISION */ |
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/* The minimum relative width of an interval. When an interval */ |
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/* is narrower than RELTOL times the larger (in */ |
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/* magnitude) endpoint, then it is considered to be */ |
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/* sufficiently small, i.e., converged. Note: this should */ |
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/* always be at least radix*machine epsilon. */ |
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/* D (input) DOUBLE PRECISION array, dimension (N) */ |
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/* The n diagonal elements of the tridiagonal matrix T. */ |
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/* E (input) DOUBLE PRECISION array, dimension (N-1) */ |
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/* The (n-1) off-diagonal elements of the tridiagonal matrix T. */ |
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/* E2 (input) DOUBLE PRECISION array, dimension (N-1) */ |
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/* The (n-1) squared off-diagonal elements of the tridiagonal matrix T. */ |
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/* PIVMIN (input) DOUBLE PRECISION */ |
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/* The minimum pivot allowed in the Sturm sequence for T. */ |
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/* NSPLIT (input) INTEGER */ |
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/* The number of diagonal blocks in the matrix T. */ |
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/* 1 <= NSPLIT <= N. */ |
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/* ISPLIT (input) INTEGER array, dimension (N) */ |
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/* The splitting points, at which T breaks up into submatrices. */ |
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/* The first submatrix consists of rows/columns 1 to ISPLIT(1), */ |
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/* the second of rows/columns ISPLIT(1)+1 through ISPLIT(2), */ |
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/* etc., and the NSPLIT-th consists of rows/columns */ |
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/* ISPLIT(NSPLIT-1)+1 through ISPLIT(NSPLIT)=N. */ |
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/* (Only the first NSPLIT elements will actually be used, but */ |
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/* since the user cannot know a priori what value NSPLIT will */ |
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/* have, N words must be reserved for ISPLIT.) */ |
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/* M (output) INTEGER */ |
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/* The actual number of eigenvalues found. 0 <= M <= N. */ |
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/* (See also the description of INFO=2,3.) */ |
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/* W (output) DOUBLE PRECISION array, dimension (N) */ |
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/* On exit, the first M elements of W will contain the */ |
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/* eigenvalue approximations. DLARRD computes an interval */ |
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/* I_j = (a_j, b_j] that includes eigenvalue j. The eigenvalue */ |
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/* approximation is given as the interval midpoint */ |
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/* W(j)= ( a_j + b_j)/2. The corresponding error is bounded by */ |
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/* WERR(j) = abs( a_j - b_j)/2 */ |
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/* WERR (output) DOUBLE PRECISION array, dimension (N) */ |
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/* The error bound on the corresponding eigenvalue approximation */ |
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/* in W. */ |
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/* WL (output) DOUBLE PRECISION */ |
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/* WU (output) DOUBLE PRECISION */ |
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/* The interval (WL, WU] contains all the wanted eigenvalues. */ |
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/* If RANGE='V', then WL=VL and WU=VU. */ |
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/* If RANGE='A', then WL and WU are the global Gerschgorin bounds */ |
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/* on the spectrum. */ |
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/* If RANGE='I', then WL and WU are computed by DLAEBZ from the */ |
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/* index range specified. */ |
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/* IBLOCK (output) INTEGER array, dimension (N) */ |
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/* At each row/column j where E(j) is zero or small, the */ |
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/* matrix T is considered to split into a block diagonal */ |
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/* matrix. On exit, if INFO = 0, IBLOCK(i) specifies to which */ |
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/* block (from 1 to the number of blocks) the eigenvalue W(i) */ |
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/* belongs. (DLARRD may use the remaining N-M elements as */ |
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/* workspace.) */ |
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/* INDEXW (output) INTEGER array, dimension (N) */ |
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/* The indices of the eigenvalues within each block (submatrix); */ |
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/* for example, INDEXW(i)= j and IBLOCK(i)=k imply that the */ |
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/* i-th eigenvalue W(i) is the j-th eigenvalue in block k. */ |
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/* WORK (workspace) DOUBLE PRECISION array, dimension (4*N) */ |
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/* IWORK (workspace) INTEGER array, dimension (3*N) */ |
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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: some or all of the eigenvalues failed to converge or */ |
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/* were not computed: */ |
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/* =1 or 3: Bisection failed to converge for some */ |
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/* eigenvalues; these eigenvalues are flagged by a */ |
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/* negative block number. The effect is that the */ |
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/* eigenvalues may not be as accurate as the */ |
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/* absolute and relative tolerances. This is */ |
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/* generally caused by unexpectedly inaccurate */ |
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/* arithmetic. */ |
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/* =2 or 3: RANGE='I' only: Not all of the eigenvalues */ |
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/* IL:IU were found. */ |
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/* Effect: M < IU+1-IL */ |
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/* Cause: non-monotonic arithmetic, causing the */ |
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/* Sturm sequence to be non-monotonic. */ |
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/* Cure: recalculate, using RANGE='A', and pick */ |
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/* out eigenvalues IL:IU. In some cases, */ |
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/* increasing the PARAMETER "FUDGE" may */ |
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/* make things work. */ |
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/* = 4: RANGE='I', and the Gershgorin interval */ |
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/* initially used was too small. No eigenvalues */ |
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/* were computed. */ |
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/* Probable cause: your machine has sloppy */ |
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/* floating-point arithmetic. */ |
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/* Cure: Increase the PARAMETER "FUDGE", */ |
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/* recompile, and try again. */ |
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/* Internal Parameters */ |
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/* =================== */ |
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/* FUDGE DOUBLE PRECISION, default = 2 */ |
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/* A "fudge factor" to widen the Gershgorin intervals. Ideally, */ |
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/* a value of 1 should work, but on machines with sloppy */ |
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/* arithmetic, this needs to be larger. The default for */ |
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/* publicly released versions should be large enough to handle */ |
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/* the worst machine around. Note that this has no effect */ |
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/* on accuracy of the solution. */ |
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/* Based on contributions by */ |
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/* W. Kahan, University of California, Berkeley, USA */ |
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/* Beresford Parlett, University of California, Berkeley, USA */ |
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/* Jim Demmel, University of California, Berkeley, USA */ |
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/* Inderjit Dhillon, University of Texas, Austin, USA */ |
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/* Osni Marques, LBNL/NERSC, USA */ |
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/* Christof Voemel, University of California, 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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/* .. Local Arrays .. */ |
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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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/* Parameter adjustments */ |
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--iwork; |
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--work; |
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--indexw; |
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--iblock; |
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--werr; |
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--w; |
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--isplit; |
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--e2; |
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--e; |
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--d__; |
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--gers; |
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/* Function Body */ |
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*info = 0; |
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/* Decode RANGE */ |
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if (lsame_(range, "A")) { |
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irange = 1; |
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} else if (lsame_(range, "V")) { |
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irange = 2; |
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} else if (lsame_(range, "I")) { |
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irange = 3; |
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} else { |
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irange = 0; |
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} |
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/* Check for Errors */ |
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if (irange <= 0) { |
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*info = -1; |
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} else if (! (lsame_(order, "B") || lsame_(order, |
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"E"))) { |
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*info = -2; |
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} else if (*n < 0) { |
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*info = -3; |
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} else if (irange == 2) { |
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if (*vl >= *vu) { |
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*info = -5; |
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} |
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} else if (irange == 3 && (*il < 1 || *il > max(1,*n))) { |
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*info = -6; |
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} else if (irange == 3 && (*iu < min(*n,*il) || *iu > *n)) { |
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*info = -7; |
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} |
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if (*info != 0) { |
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return 0; |
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} |
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/* Initialize error flags */ |
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*info = 0; |
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ncnvrg = FALSE_; |
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toofew = FALSE_; |
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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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return 0; |
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} |
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/* Simplification: */ |
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if (irange == 3 && *il == 1 && *iu == *n) { |
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irange = 1; |
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} |
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/* Get machine constants */ |
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eps = dlamch_("P"); |
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uflow = dlamch_("U"); |
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/* Special Case when N=1 */ |
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/* Treat case of 1x1 matrix for quick return */ |
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if (*n == 1) { |
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if (irange == 1 || irange == 2 && d__[1] > *vl && d__[1] <= *vu || |
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irange == 3 && *il == 1 && *iu == 1) { |
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*m = 1; |
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w[1] = d__[1]; |
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/* The computation error of the eigenvalue is zero */ |
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werr[1] = 0.; |
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iblock[1] = 1; |
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indexw[1] = 1; |
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} |
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return 0; |
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} |
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/* NB is the minimum vector length for vector bisection, or 0 */ |
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/* if only scalar is to be done. */ |
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nb = ilaenv_(&c__1, "DSTEBZ", " ", n, &c_n1, &c_n1, &c_n1); |
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if (nb <= 1) { |
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nb = 0; |
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} |
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/* Find global spectral radius */ |
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gl = d__[1]; |
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gu = d__[1]; |
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i__1 = *n; |
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for (i__ = 1; i__ <= i__1; ++i__) { |
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/* Computing MIN */ |
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d__1 = gl, d__2 = gers[(i__ << 1) - 1]; |
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gl = min(d__1,d__2); |
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/* Computing MAX */ |
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d__1 = gu, d__2 = gers[i__ * 2]; |
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gu = max(d__1,d__2); |
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/* L5: */ |
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} |
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/* Compute global Gerschgorin bounds and spectral diameter */ |
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/* Computing MAX */ |
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d__1 = abs(gl), d__2 = abs(gu); |
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tnorm = max(d__1,d__2); |
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gl = gl - tnorm * 2. * eps * *n - *pivmin * 4.; |
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gu = gu + tnorm * 2. * eps * *n + *pivmin * 4.; |
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/* [JAN/28/2009] remove the line below since SPDIAM variable not use */ |
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/* SPDIAM = GU - GL */ |
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/* Input arguments for DLAEBZ: */ |
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/* The relative tolerance. An interval (a,b] lies within */ |
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/* "relative tolerance" if b-a < RELTOL*max(|a|,|b|), */ |
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rtoli = *reltol; |
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/* Set the absolute tolerance for interval convergence to zero to force */ |
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/* interval convergence based on relative size of the interval. */ |
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/* This is dangerous because intervals might not converge when RELTOL is */ |
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/* small. But at least a very small number should be selected so that for */ |
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/* strongly graded matrices, the code can get relatively accurate */ |
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/* eigenvalues. */ |
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atoli = uflow * 4. + *pivmin * 4.; |
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if (irange == 3) { |
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/* RANGE='I': Compute an interval containing eigenvalues */ |
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/* IL through IU. The initial interval [GL,GU] from the global */ |
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/* Gerschgorin bounds GL and GU is refined by DLAEBZ. */ |
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itmax = (integer) ((log(tnorm + *pivmin) - log(*pivmin)) / log(2.)) + |
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2; |
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work[*n + 1] = gl; |
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work[*n + 2] = gl; |
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work[*n + 3] = gu; |
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work[*n + 4] = gu; |
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work[*n + 5] = gl; |
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work[*n + 6] = gu; |
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iwork[1] = -1; |
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iwork[2] = -1; |
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iwork[3] = *n + 1; |
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iwork[4] = *n + 1; |
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iwork[5] = *il - 1; |
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iwork[6] = *iu; |
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dlaebz_(&c__3, &itmax, n, &c__2, &c__2, &nb, &atoli, &rtoli, pivmin, & |
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d__[1], &e[1], &e2[1], &iwork[5], &work[*n + 1], &work[*n + 5] |
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, &iout, &iwork[1], &w[1], &iblock[1], &iinfo); |
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if (iinfo != 0) { |
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*info = iinfo; |
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return 0; |
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} |
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/* On exit, output intervals may not be ordered by ascending negcount */ |
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if (iwork[6] == *iu) { |
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*wl = work[*n + 1]; |
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wlu = work[*n + 3]; |
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nwl = iwork[1]; |
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*wu = work[*n + 4]; |
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wul = work[*n + 2]; |
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nwu = iwork[4]; |
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} else { |
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*wl = work[*n + 2]; |
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wlu = work[*n + 4]; |
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nwl = iwork[2]; |
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*wu = work[*n + 3]; |
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wul = work[*n + 1]; |
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nwu = iwork[3]; |
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} |
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/* On exit, the interval [WL, WLU] contains a value with negcount NWL, */ |
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/* and [WUL, WU] contains a value with negcount NWU. */ |
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if (nwl < 0 || nwl >= *n || nwu < 1 || nwu > *n) { |
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*info = 4; |
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return 0; |
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} |
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} else if (irange == 2) { |
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*wl = *vl; |
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*wu = *vu; |
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} else if (irange == 1) { |
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*wl = gl; |
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*wu = gu; |
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} |
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/* Find Eigenvalues -- Loop Over blocks and recompute NWL and NWU. */ |
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/* NWL accumulates the number of eigenvalues .le. WL, */ |
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/* NWU accumulates the number of eigenvalues .le. WU */ |
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*m = 0; |
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iend = 0; |
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*info = 0; |
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nwl = 0; |
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nwu = 0; |
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i__1 = *nsplit; |
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for (jblk = 1; jblk <= i__1; ++jblk) { |
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ioff = iend; |
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ibegin = ioff + 1; |
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iend = isplit[jblk]; |
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in = iend - ioff; |
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if (in == 1) { |
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/* 1x1 block */ |
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if (*wl >= d__[ibegin] - *pivmin) { |
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++nwl; |
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} |
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if (*wu >= d__[ibegin] - *pivmin) { |
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++nwu; |
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} |
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if (irange == 1 || *wl < d__[ibegin] - *pivmin && *wu >= d__[ |
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ibegin] - *pivmin) { |
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++(*m); |
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w[*m] = d__[ibegin]; |
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werr[*m] = 0.; |
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/* The gap for a single block doesn't matter for the later */ |
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/* algorithm and is assigned an arbitrary large value */ |
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iblock[*m] = jblk; |
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indexw[*m] = 1; |
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} |
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/* Disabled 2x2 case because of a failure on the following matrix */ |
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/* RANGE = 'I', IL = IU = 4 */ |
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/* Original Tridiagonal, d = [ */ |
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/* -0.150102010615740E+00 */ |
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/* -0.849897989384260E+00 */ |
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/* -0.128208148052635E-15 */ |
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/* 0.128257718286320E-15 */ |
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/* ]; */ |
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/* e = [ */ |
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/* -0.357171383266986E+00 */ |
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/* -0.180411241501588E-15 */ |
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/* -0.175152352710251E-15 */ |
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/* ]; */ |
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/* ELSE IF( IN.EQ.2 ) THEN */ |
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/* * 2x2 block */ |
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/* DISC = SQRT( (HALF*(D(IBEGIN)-D(IEND)))**2 + E(IBEGIN)**2 ) */ |
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/* TMP1 = HALF*(D(IBEGIN)+D(IEND)) */ |
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/* L1 = TMP1 - DISC */ |
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/* IF( WL.GE. L1-PIVMIN ) */ |
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/* $ NWL = NWL + 1 */ |
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/* IF( WU.GE. L1-PIVMIN ) */ |
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/* $ NWU = NWU + 1 */ |
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/* IF( IRANGE.EQ.ALLRNG .OR. ( WL.LT.L1-PIVMIN .AND. WU.GE. */ |
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/* $ L1-PIVMIN ) ) THEN */ |
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/* M = M + 1 */ |
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/* W( M ) = L1 */ |
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/* * The uncertainty of eigenvalues of a 2x2 matrix is very small */ |
|
/* WERR( M ) = EPS * ABS( W( M ) ) * TWO */ |
|
/* IBLOCK( M ) = JBLK */ |
|
/* INDEXW( M ) = 1 */ |
|
/* ENDIF */ |
|
/* L2 = TMP1 + DISC */ |
|
/* IF( WL.GE. L2-PIVMIN ) */ |
|
/* $ NWL = NWL + 1 */ |
|
/* IF( WU.GE. L2-PIVMIN ) */ |
|
/* $ NWU = NWU + 1 */ |
|
/* IF( IRANGE.EQ.ALLRNG .OR. ( WL.LT.L2-PIVMIN .AND. WU.GE. */ |
|
/* $ L2-PIVMIN ) ) THEN */ |
|
/* M = M + 1 */ |
|
/* W( M ) = L2 */ |
|
/* * The uncertainty of eigenvalues of a 2x2 matrix is very small */ |
|
/* WERR( M ) = EPS * ABS( W( M ) ) * TWO */ |
|
/* IBLOCK( M ) = JBLK */ |
|
/* INDEXW( M ) = 2 */ |
|
/* ENDIF */ |
|
} else { |
|
/* General Case - block of size IN >= 2 */ |
|
/* Compute local Gerschgorin interval and use it as the initial */ |
|
/* interval for DLAEBZ */ |
|
gu = d__[ibegin]; |
|
gl = d__[ibegin]; |
|
tmp1 = 0.; |
|
i__2 = iend; |
|
for (j = ibegin; j <= i__2; ++j) { |
|
/* Computing MIN */ |
|
d__1 = gl, d__2 = gers[(j << 1) - 1]; |
|
gl = min(d__1,d__2); |
|
/* Computing MAX */ |
|
d__1 = gu, d__2 = gers[j * 2]; |
|
gu = max(d__1,d__2); |
|
/* L40: */ |
|
} |
|
/* [JAN/28/2009] */ |
|
/* change SPDIAM by TNORM in lines 2 and 3 thereafter */ |
|
/* line 1: remove computation of SPDIAM (not useful anymore) */ |
|
/* SPDIAM = GU - GL */ |
|
/* GL = GL - FUDGE*SPDIAM*EPS*IN - FUDGE*PIVMIN */ |
|
/* GU = GU + FUDGE*SPDIAM*EPS*IN + FUDGE*PIVMIN */ |
|
gl = gl - tnorm * 2. * eps * in - *pivmin * 2.; |
|
gu = gu + tnorm * 2. * eps * in + *pivmin * 2.; |
|
|
|
if (irange > 1) { |
|
if (gu < *wl) { |
|
/* the local block contains none of the wanted eigenvalues */ |
|
nwl += in; |
|
nwu += in; |
|
goto L70; |
|
} |
|
/* refine search interval if possible, only range (WL,WU] matters */ |
|
gl = max(gl,*wl); |
|
gu = min(gu,*wu); |
|
if (gl >= gu) { |
|
goto L70; |
|
} |
|
} |
|
/* Find negcount of initial interval boundaries GL and GU */ |
|
work[*n + 1] = gl; |
|
work[*n + in + 1] = gu; |
|
dlaebz_(&c__1, &c__0, &in, &in, &c__1, &nb, &atoli, &rtoli, |
|
pivmin, &d__[ibegin], &e[ibegin], &e2[ibegin], idumma, & |
|
work[*n + 1], &work[*n + (in << 1) + 1], &im, &iwork[1], & |
|
w[*m + 1], &iblock[*m + 1], &iinfo); |
|
if (iinfo != 0) { |
|
*info = iinfo; |
|
return 0; |
|
} |
|
|
|
nwl += iwork[1]; |
|
nwu += iwork[in + 1]; |
|
iwoff = *m - iwork[1]; |
|
/* Compute Eigenvalues */ |
|
itmax = (integer) ((log(gu - gl + *pivmin) - log(*pivmin)) / log( |
|
2.)) + 2; |
|
dlaebz_(&c__2, &itmax, &in, &in, &c__1, &nb, &atoli, &rtoli, |
|
pivmin, &d__[ibegin], &e[ibegin], &e2[ibegin], idumma, & |
|
work[*n + 1], &work[*n + (in << 1) + 1], &iout, &iwork[1], |
|
&w[*m + 1], &iblock[*m + 1], &iinfo); |
|
if (iinfo != 0) { |
|
*info = iinfo; |
|
return 0; |
|
} |
|
|
|
/* Copy eigenvalues into W and IBLOCK */ |
|
/* Use -JBLK for block number for unconverged eigenvalues. */ |
|
/* Loop over the number of output intervals from DLAEBZ */ |
|
i__2 = iout; |
|
for (j = 1; j <= i__2; ++j) { |
|
/* eigenvalue approximation is middle point of interval */ |
|
tmp1 = (work[j + *n] + work[j + in + *n]) * .5; |
|
/* semi length of error interval */ |
|
tmp2 = (d__1 = work[j + *n] - work[j + in + *n], abs(d__1)) * |
|
.5; |
|
if (j > iout - iinfo) { |
|
/* Flag non-convergence. */ |
|
ncnvrg = TRUE_; |
|
ib = -jblk; |
|
} else { |
|
ib = jblk; |
|
} |
|
i__3 = iwork[j + in] + iwoff; |
|
for (je = iwork[j] + 1 + iwoff; je <= i__3; ++je) { |
|
w[je] = tmp1; |
|
werr[je] = tmp2; |
|
indexw[je] = je - iwoff; |
|
iblock[je] = ib; |
|
/* L50: */ |
|
} |
|
/* L60: */ |
|
} |
|
|
|
*m += im; |
|
} |
|
L70: |
|
; |
|
} |
|
/* If RANGE='I', then (WL,WU) contains eigenvalues NWL+1,...,NWU */ |
|
/* If NWL+1 < IL or NWU > IU, discard extra eigenvalues. */ |
|
if (irange == 3) { |
|
idiscl = *il - 1 - nwl; |
|
idiscu = nwu - *iu; |
|
|
|
if (idiscl > 0) { |
|
im = 0; |
|
i__1 = *m; |
|
for (je = 1; je <= i__1; ++je) { |
|
/* Remove some of the smallest eigenvalues from the left so that */ |
|
/* at the end IDISCL =0. Move all eigenvalues up to the left. */ |
|
if (w[je] <= wlu && idiscl > 0) { |
|
--idiscl; |
|
} else { |
|
++im; |
|
w[im] = w[je]; |
|
werr[im] = werr[je]; |
|
indexw[im] = indexw[je]; |
|
iblock[im] = iblock[je]; |
|
} |
|
/* L80: */ |
|
} |
|
*m = im; |
|
} |
|
if (idiscu > 0) { |
|
/* Remove some of the largest eigenvalues from the right so that */ |
|
/* at the end IDISCU =0. Move all eigenvalues up to the left. */ |
|
im = *m + 1; |
|
for (je = *m; je >= 1; --je) { |
|
if (w[je] >= wul && idiscu > 0) { |
|
--idiscu; |
|
} else { |
|
--im; |
|
w[im] = w[je]; |
|
werr[im] = werr[je]; |
|
indexw[im] = indexw[je]; |
|
iblock[im] = iblock[je]; |
|
} |
|
/* L81: */ |
|
} |
|
jee = 0; |
|
i__1 = *m; |
|
for (je = im; je <= i__1; ++je) { |
|
++jee; |
|
w[jee] = w[je]; |
|
werr[jee] = werr[je]; |
|
indexw[jee] = indexw[je]; |
|
iblock[jee] = iblock[je]; |
|
/* L82: */ |
|
} |
|
*m = *m - im + 1; |
|
} |
|
if (idiscl > 0 || idiscu > 0) { |
|
/* Code to deal with effects of bad arithmetic. (If N(w) is */ |
|
/* monotone non-decreasing, this should never happen.) */ |
|
/* Some low eigenvalues to be discarded are not in (WL,WLU], */ |
|
/* or high eigenvalues to be discarded are not in (WUL,WU] */ |
|
/* so just kill off the smallest IDISCL/largest IDISCU */ |
|
/* eigenvalues, by marking the corresponding IBLOCK = 0 */ |
|
if (idiscl > 0) { |
|
wkill = *wu; |
|
i__1 = idiscl; |
|
for (jdisc = 1; jdisc <= i__1; ++jdisc) { |
|
iw = 0; |
|
i__2 = *m; |
|
for (je = 1; je <= i__2; ++je) { |
|
if (iblock[je] != 0 && (w[je] < wkill || iw == 0)) { |
|
iw = je; |
|
wkill = w[je]; |
|
} |
|
/* L90: */ |
|
} |
|
iblock[iw] = 0; |
|
/* L100: */ |
|
} |
|
} |
|
if (idiscu > 0) { |
|
wkill = *wl; |
|
i__1 = idiscu; |
|
for (jdisc = 1; jdisc <= i__1; ++jdisc) { |
|
iw = 0; |
|
i__2 = *m; |
|
for (je = 1; je <= i__2; ++je) { |
|
if (iblock[je] != 0 && (w[je] >= wkill || iw == 0)) { |
|
iw = je; |
|
wkill = w[je]; |
|
} |
|
/* L110: */ |
|
} |
|
iblock[iw] = 0; |
|
/* L120: */ |
|
} |
|
} |
|
/* Now erase all eigenvalues with IBLOCK set to zero */ |
|
im = 0; |
|
i__1 = *m; |
|
for (je = 1; je <= i__1; ++je) { |
|
if (iblock[je] != 0) { |
|
++im; |
|
w[im] = w[je]; |
|
werr[im] = werr[je]; |
|
indexw[im] = indexw[je]; |
|
iblock[im] = iblock[je]; |
|
} |
|
/* L130: */ |
|
} |
|
*m = im; |
|
} |
|
if (idiscl < 0 || idiscu < 0) { |
|
toofew = TRUE_; |
|
} |
|
} |
|
|
|
if (irange == 1 && *m != *n || irange == 3 && *m != *iu - *il + 1) { |
|
toofew = TRUE_; |
|
} |
|
/* If ORDER='B', do nothing the eigenvalues are already sorted by */ |
|
/* block. */ |
|
/* If ORDER='E', sort the eigenvalues from smallest to largest */ |
|
if (lsame_(order, "E") && *nsplit > 1) { |
|
i__1 = *m - 1; |
|
for (je = 1; je <= i__1; ++je) { |
|
ie = 0; |
|
tmp1 = w[je]; |
|
i__2 = *m; |
|
for (j = je + 1; j <= i__2; ++j) { |
|
if (w[j] < tmp1) { |
|
ie = j; |
|
tmp1 = w[j]; |
|
} |
|
/* L140: */ |
|
} |
|
if (ie != 0) { |
|
tmp2 = werr[ie]; |
|
itmp1 = iblock[ie]; |
|
itmp2 = indexw[ie]; |
|
w[ie] = w[je]; |
|
werr[ie] = werr[je]; |
|
iblock[ie] = iblock[je]; |
|
indexw[ie] = indexw[je]; |
|
w[je] = tmp1; |
|
werr[je] = tmp2; |
|
iblock[je] = itmp1; |
|
indexw[je] = itmp2; |
|
} |
|
/* L150: */ |
|
} |
|
} |
|
|
|
*info = 0; |
|
if (ncnvrg) { |
|
++(*info); |
|
} |
|
if (toofew) { |
|
*info += 2; |
|
} |
|
return 0; |
|
|
|
/* End of DLARRD */ |
|
|
|
} /* dlarrd_ */
|
|
|