November 2014 - GiNaC-devel

04 Jun '15

Hi, is there any reason not to define the derivative of the built-in abs() function as either abs(x)/x or csgn(x) ? Currently it has not derivative defined at all. Regards, Jan

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Implicit derivation of functions (re-submission)
by Vladimir V. Kisil 02 Feb '15

02 Feb '15

Dear All, I am resending the patch for implicit derivation of functions. Quote from the previous submission: http://www.ginac.de/pipermail/ginac-devel/2013-November/002053.html " I wish to propose another GiNaC extension. Consider function abs(). Since it can be presented as abs(z)=sqrt(z*z.conjugate()), the derivative of abs(f) may be calculated as (abs(f))'=(f'*f.conjugate()+f*f'.conjugate())/2/abs(f) However, this formula cannot be packed into the present GiNaC code, since it only knows about the chain rule. Thus, the patch adds a possibility to define derivatives of functions in some general expression. In particular, the above derivative of abs() is defined. Example: cout << abs(log(z)).diff(z) << endl; // (before) -> D[0](abs)(log(z))*z^(-1) // (now) -> 1/2*(z^(-1)*conjugate(log(z))+log(z)*conjugate(z)^(-1))*abs(log(z))^(-1) " This issue independently appeared in this discussion: http://www.ginac.de/pipermail/ginac-devel/2014-April/002106.html If it is not included in the core code, then a user need to redefine the entire GiNaC function class to have this feature. Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk -- www: http://maths.leeds.ac.uk/~kisilv/

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Re: [GiNaC-devel] morusaka@libero.it n
by morusaka 29 Nov '14

29 Nov '14

http://www.sawserviceab.com/eowk/rmdzywxjyujxqzhqtjjhenuvric.ikiesnlnuekovn… morusaka(a)libero.it

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Release 1.6.3
by Richard B. Kreckel 28 Nov '14

28 Nov '14

Hi everybody, Alexei and I have prepared a new release and are happy to announce that GiNaC 1.6.3 is out and available. These are the changes: * New expand_options::expand_transcendental. GiNaC will apply additional rules when expanding expressions if this option is specified, i.e. log(a*b) -> log(a) + log(b) exp(a + b) -> exp(a)*exp(b) * Functions can define a custom expand() and info() now. * Automatically rewrite (x^{-1})^c -> x^{-c} for positive c. * Transform abs(x)^n -> x^n if x is real and n is even. * Improved power::info(): power with a real base and even exponent reports that it's non-negative. * Fixed spurious match failure due to expairseq::match() bug: > match(sin(y)*exp(b)+sin(x)*exp(a), sin($0)*exp(a)+exp(b)*sin($1)) FAIL * Fixed power::is_polynomial() and mul::is_polynomial() computation. * factor_univariate correctly handles polynomials over rationals (no segfaults any more). * Fixed an infinite loop in factor_multivariate due to incorrect handling of polynomials having a leading coefficient being a sum with a non-trivial integer content. * Fixed numeric evaluation of generalized multiple polylogarithms for real and negative argument. * Avoid calling log(1-x) in numeric evaluation of classical polylogarithm. * Fixed numeric evaluation of multiple polylogarithms (correctly set the signs of the imaginary parts in the intermediate expression). * Fixed numeric evaluation of Nielsen polylogs for arguments close to the 6th root of unity or its conjugate. * Avoid infinite recursion in series expansion of logarithm. * numeric::info(info_flags::nonnegative) correctly handles complex numbers with non-zero imaginary part. * Fixed several build issues: - libreadline and dlopen() misdetection. - multiple definition of symbol on MinGW. - auto* tools and texinfo being unhappy in various ways. * GiNaC can be built with CMake now. Regards, -richy. -- Richard B. Kreckel <http://in.terlu.de/~kreckel/>

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[SCM] GiNaC -- a C++ library for symbolic computations tag, ginac_1-6-3, created. release_1-4-0-437-gcfdc2c3
by git＠ginac.de 27 Nov '14

27 Nov '14

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 tag, ginac_1-6-3 has been created at cfdc2c31088bb196426dd071de5181248df2e160 (commit) - Log ----------------------------------------------------------------- commit cfdc2c31088bb196426dd071de5181248df2e160 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Thu Nov 27 21:29:39 2014 +0000 Finalized 1.6.3 release. Updated NEWS file, moved some comments so Doxygen won't be confused. ----------------------------------------------------------------------- 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_1-4-0-437-gcfdc2c3
by git＠ginac.de 27 Nov '14

27 Nov '14

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 cfdc2c31088bb196426dd071de5181248df2e160 (commit) from 55a08d9cb9005bb10def92d5e8f5a816003da16b (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 cfdc2c31088bb196426dd071de5181248df2e160 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Thu Nov 27 21:29:39 2014 +0000 Finalized 1.6.3 release. Updated NEWS file, moved some comments so Doxygen won't be confused. ----------------------------------------------------------------------- Summary of changes: NEWS | 11 ++++------- ginac/crc32.h | 8 +++++--- ginac/hash_seed.h | 27 ++++++++++++++++----------- 3 files changed, 25 insertions(+), 21 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[SCM] GiNaC -- a C++ library for symbolic computations tag, release_1-6-3, created. release_1-4-0-437-g2c7d26f
by git＠ginac.de 27 Nov '14

27 Nov '14

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 tag, release_1-6-3 has been created at 2c7d26f82ab2938ccc42372459a6640137a910a1 (commit) - Log ----------------------------------------------------------------- commit 2c7d26f82ab2938ccc42372459a6640137a910a1 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Thu Nov 27 21:29:39 2014 +0000 Finilized 1.6.3 release. Updated NEWS file, moved some comments so Doxygen won't be confused. ----------------------------------------------------------------------- hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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