[GiNaC-devel] [SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-218-ge75c7a3

[Richard B. Kreckel]

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- Log -----------------------------------------------------------------
commit e75c7a32a0ea156635aeec535b9cdf7d4bf3f9b9
Author: Alexei Sheplyakov <alexei.sheplyakov at gmail.com>
Date:   Tue May 18 00:23:03 2010 +0200

    pgcd(), chinrem_gcd(): use appropriate definition of the degree.
    
    Effect: fixes (rare) GCD miscalculation.
    
    pgcd() treats polynomials Z_p[x_0, ..., x_n] as R[x_0, ..., x_{n - 1}], where
    R = Z_p[x_n]. Therefore one should use correct definition of the degree
    (i.e. compute it w.r.t. x_0, ..., x_{n-1}, but NOT w.r.t. x_n!).
    
    One should use appropriate definition of degree (that is, w.r.t.  x_0, ..., x_n)
    in chinrem_gcd() too.
    
    Thanks to Aless Lasaruk for a bug report.

commit b2ea74ecbae56d737aacf2cbb418d7c9998718a4
Author: Alexei Sheplyakov <alexei.sheplyakov at gmail.com>
Date:   Tue May 18 00:21:53 2010 +0200

    Added `degree_vector' utility function.
    
    It's a generalization of degree(expr, var) for multivariate polynomials.

commit 5432feb4dae4c48f3b652d661aa323f07d20c00b
Author: Alexei Sheplyakov <alexei.sheplyakov at gmail.com>
Date:   Tue May 18 00:20:08 2010 +0200

    primpart_content: correctly handle monomials.
    
    Impact: fixes (rare) incorrect gcd calculation and (potential) segfault.
    
    Thanks to Aless Lasaruk for a bug report.

commit 8fcaff0d29e20d570c2936a27ce110326b76390e
Author: Alexei Sheplyakov <alexei.sheplyakov at gmail.com>
Date:   Tue May 18 00:17:26 2010 +0200

    pgcd(): avoid infinite loop if the first GCD candidate coincides with GCD
    
    136	if (H_lcoeff.is_equal(lc_gcd)) {
    137		if ((Hprev-H).expand().smod(pn).is_zero()) // (*)
    138			continue;
    
    The check (*) can result in infinite loop if the (very) first GCD candidate
    gives the correct GCD: any subsequent iterations give the same result, so
    Hprev and H will be equal (hence the infinite loop). That check is not very
    useful (AFAIR I was trying to avoid extra division checks), so let's remove it.

commit 0c1db90c39613c27a088b760d68e8d59d4a12ee3
Author: Richard Kreckel <kreckel at ginac.de>
Date:   Mon May 17 08:37:08 2010 +0200

    Fix URL of CODA.

-----------------------------------------------------------------------

Summary of changes:
 check/Makefile.am                     |    4 +++
 check/pgcd_infinite_loop.cpp          |   41 +++++++++++++++++++++++++++++++++
 doc/tutorial/ginac.texi               |    2 +-
 ginac/polynomial/collect_vargs.cpp    |   22 ++++++++++++++++-
 ginac/polynomial/collect_vargs.h      |   31 +++++++++++++++++++++++++
 ginac/polynomial/mgcd.cpp             |   12 ++++++---
 ginac/polynomial/pgcd.cpp             |   12 +++++-----
 ginac/polynomial/primpart_content.cpp |    2 +-
 8 files changed, 112 insertions(+), 14 deletions(-)
 create mode 100644 check/pgcd_infinite_loop.cpp


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GiNaC -- a C++ library for symbolic computations