November 2013 - GiNaC-devel

Fixing log evaluation for powers
by Vladimir V. Kisil 29 Dec '13

29 Dec '13

Dear All, Making check on current master, I noticed that the following test if (!ex(log(pow(p,a))).is_equal(a*log(p))) ++result; from exam_inifnc.cpp failed. I think that the evaluation rule log(p^a) -> a*log(p), if p>0 and a is real falls out of inifcns_trans.cpp. I am attaching the corresponding patch. Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk www: http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Transformations http://www.worldscientific.com/worldscibooks/10.1142/p835

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Derivative of conjugated is conjugated of derivative.
by Vladimir V. Kisil 09 Nov '13

09 Nov '13

Dear All, Further to my previous patch on functions derivatives, this small patch adds the rule conjugate(f)'=conjugate(f') to the GiNaC. The change can be seen here: cout << conjugate(log(z)).diff(z) << endl; // (before) -> z^(-1)*D[0](conjugate)(log(z)) // (now) -> conjugate(z)^(-1) Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk www: http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Transformations http://www.worldscientific.com/worldscibooks/10.1142/p835

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Roots of polynomial
by Rekha Penmetsa 08 Nov '13

08 Nov '13

Hi, I am using GiNaC in my project. I want to find roots of a univariate polynomial. I am deriving a polynomial from a matrix determinant, which is coming to, 6-1/15*r-19/3138418483200*r^4-23/20713561989120000*r^5+1/18900*r^2-71/7264857600*r^3 I am using RealAlgebraicNumberFactory::realRoots() method as in the below code to find roots. I have installed GiNaCRA as well and example programs are compiling and running fine. RationalUnivariatePolynomial p(det,r); list<RealAlgebraicNumberPtr> roots = RealAlgebraicNumberFactory::realRoots( p ); This call is returning a list of zero size. Am I missing anything ? how to solve for roots for polynomials of this type? Thanks Rekha

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Even powers of modulus are rationalized
by Vladimir V. Kisil 05 Nov '13

05 Nov '13

Dear All, I believe that |z|^2= z*conjugate(z) is valid for any z. Also, the automatic substitution abs(z)^(2n) -> z^n * conjugate(z)^n shall make an expression more rational and, thus, more accessible to GiNaC. Therefore, I propose the attached alteration of abs_power(). Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk www: http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Transformations http://www.worldscientific.com/worldscibooks/10.1142/p835

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Releasing?
by Richard B. Kreckel 04 Nov '13

04 Nov '13

Hi! Does anybody have plans for releasing? Doing releases may have become unpopular among developers since the current version can always easily be pulled off from git. On the other hand, we've had quite a number of improvements and build fixes since 1.6.2, so it might be a good opportunity to officially get all this released. What do others think? And, in particular, @Alex and @Vladimir: do you have things in the pipeline? Cheers -richy. -- Richard B. Kreckel <http://www.ginac.de/~kreckel/>

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-405-ge5c76f6
by git＠ginac.de 03 Nov '13

03 Nov '13

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, master has been updated via e5c76f659e2e882da3d5dba60502d6851f782bf3 (commit) via 5a3641098c88d3c6ea0765df65b801312ecfb91b (commit) from 5bf87cea66bb2071222c2910ed68c2649a98906c (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit e5c76f659e2e882da3d5dba60502d6851f782bf3 Author: Vladimir V. Kisil <kisilv(a)maths.leeds.ac.uk> Date: Sun Nov 3 22:21:00 2013 +0200 Expansion rules for exp(), log(), and abs(). exp(a + b) -> exp(a)*exp(b) log(a*b) -> log(a) + log(b) abs(z*w) -> abs(z)*abs(w) log and exp are transformed only if expand_options::expand_transcendental is given. Signed-off-by: Vladimir V. Kisil <kisilv(a)maths.leeds.ac.uk> commit 5a3641098c88d3c6ea0765df65b801312ecfb91b Author: Vladimir V. Kisil <kisilv(a)maths.leeds.ac.uk> Date: Sat Nov 2 21:06:53 2013 +0200 Introduce expand_options::expand_transcendental. In general expand() treats the argument as a rational expression (and leave transcendental functions as they are). However sometimes it's convenient to expand transcendental functions too, like log(a*b) = log(a) + log(b) exp(a + b) = exp(a)*exp(b) Applying such transformation by default doesn't seem to be a smart idea (think of log(p^2/mu^2) transformed to 2*log(p) - 2*log(mu)). Therefore introduce expand_options::expand_transcendental. As the name implies expand() tries to transform transcendental functions only if this flag is set. Signed-off-by: Vladimir V. Kisil <kisilv(a)maths.leeds.ac.uk> ----------------------------------------------------------------------- Summary of changes: check/exam_inifcns.cpp | 65 ++++++++++++++++++++++++++++++++++++++++++ doc/tutorial/ginac.texi | 53 ++++++++++++++++++++++++++++++++++ ginac/flags.h | 3 +- ginac/inifcns.cpp | 22 ++++++++++++++ ginac/inifcns_trans.cpp | 72 +++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 214 insertions(+), 1 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-403-g5bf87ce
by git＠ginac.de 03 Nov '13

03 Nov '13

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, master has been updated via 5bf87cea66bb2071222c2910ed68c2649a98906c (commit) from 0eb0cb55c76ceab744847d6e66533e292774e1cb (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 5bf87cea66bb2071222c2910ed68c2649a98906c Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Nov 3 12:49:07 2013 +0000 Keep CLang/libc++ happy. ----------------------------------------------------------------------- Summary of changes: ginac/inifcns_nstdsums.cpp | 28 ++++++++++++++-------------- 1 files changed, 14 insertions(+), 14 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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