April 2019 - GiNaC-devel

evalf() on cube roots
by Jan Rheinländer 21 Sep '19

21 Sep '19

Picking up this old thread... I would like to submit a patch that allows choosing the convention for negative cube roots between the solution on the principal branch and the real-valued solution. That is, in the cln library, file complex/transcendental/cl_C_expt_C.cc I would like to handle the following case separately: y rational and y ratio m/n x rational and x < 0 n odd What about introducing a flag called (e.g.) cln::cl_odd_roots_of_rationals_real (similar to cln::cl_inhibit_floating_point_underflow)? If the flag is false (default), the above case evaluates to exp(log(x) * y) as before If the flag is true, it evaluates to (-1)^m * (-x)^(m/n) Would such a patch be acceptable? Greetings, Jan Rheinländer Am 02.08.2015 um 21:55 schrieb Richard B. Kreckel: > On 08/02/2015 08:59 PM, Jan Rheinländer wrote: >>> There isn't. GiNaC, like almost all other systems, returns the solution >>> on the principal branch, compatible with exp(log(-1)/3). >> I suppose there is some excellent mathematical reason for this... > Actually, there isn't. Branch cuts are a matter of convention. > Nothing more but also nothing less. > >> but for >> me it means that I can't use GiNaC to verify Cardano's formula for a >> cubic function: >> >>> x = (-1 - sqrt(2))^(1/3) + (-1 + sqrt(2))^(1/3); >> (-1-sqrt(2))^(1/3)+(-1+sqrt(2))^(1/3) >> >>> evalf(x^3 + 3 * x + 2); >> 3.3544445609126528848+8.9073474964875349776*I >> >> Surely there must be a way to verify such a formula in GiNaC??? > It should be straightforward to replace such rational expressions by the > form you want them to be in before calling evalf(), using techniques > such as these: <http://www.ginac.de/FAQ.html#advanced> > > Cheers > -richy.

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Release 1.7.6
by Richard B. Kreckel 22 Apr '19

22 Apr '19

Hi, A new GiNaC version has just been released. The changes are: * Fix a bug in mul::series() about asymptotic order term. * Fix cl_N code generation for small negative integers. * Fix multiple polylog computation related to trailing zeros and user-specified signs for small imaginary parts. * Fix CMake build with Python3. Happy Easter! -richy.

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[SCM] GiNaC -- a C++ library for symbolic computations tag, list, deleted. release_1-4-0-619-g2d33e402
by Richard B. Kreckel 22 Apr '19

22 Apr '19

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, list has been deleted was 2d33e40249cafcb9a0547c282e6e6790a480e81b ----------------------------------------------------------------------- 2d33e40249cafcb9a0547c282e6e6790a480e81b Finalize 1.7.5 release. ----------------------------------------------------------------------- hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[SCM] GiNaC -- a C++ library for symbolic computations tag, list, created. release_1-4-0-619-g2d33e402
by Richard B. Kreckel 22 Apr '19

22 Apr '19

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, list has been created at 2d33e40249cafcb9a0547c282e6e6790a480e81b (commit) - Log ----------------------------------------------------------------- commit 2d33e40249cafcb9a0547c282e6e6790a480e81b Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Feb 17 12:13:10 2019 +0100 Finalize 1.7.5 release. ----------------------------------------------------------------------- hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[SCM] GiNaC -- a C++ library for symbolic computations tag, release_1-7-6, created. release_1-4-0-627-gf7884835
by Richard B. Kreckel 22 Apr '19

22 Apr '19

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_1-7-6 has been created at f7884835d397de85e648d1957c058b7d4c0948ba (commit) - Log ----------------------------------------------------------------- commit f7884835d397de85e648d1957c058b7d4c0948ba Author: Richard Kreckel <kreckel(a)ginac.de> Date: Mon Apr 22 20:14:52 2019 +0200 Finalize 1.7.6 release. ----------------------------------------------------------------------- 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_1-4-0-627-gf7884835
by Richard B. Kreckel 22 Apr '19

22 Apr '19

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 f7884835d397de85e648d1957c058b7d4c0948ba (commit) from 709e61093f43462b5816f859a32a31cc00758da8 (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 f7884835d397de85e648d1957c058b7d4c0948ba Author: Richard Kreckel <kreckel(a)ginac.de> Date: Mon Apr 22 20:14:52 2019 +0200 Finalize 1.7.6 release. ----------------------------------------------------------------------- Summary of changes: NEWS | 7 +++++++ ginac/version.h | 6 +++--- 2 files changed, 10 insertions(+), 3 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_1-4-0-626-g709e6109
by Richard B. Kreckel 21 Apr '19

21 Apr '19

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 709e61093f43462b5816f859a32a31cc00758da8 (commit) from 0b94fe8f8567e31268adede7c7ea671ef80a8558 (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 709e61093f43462b5816f859a32a31cc00758da8 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Apr 21 21:43:45 2019 +0200 Fix bug in mul::series() about asymptotic order term. This reverts db81420a6195 and adds a test case. Thanks to Feng Feng for reporting this. ----------------------------------------------------------------------- Summary of changes: check/exam_pseries.cpp | 4 ++++ ginac/pseries.cpp | 5 ++--- 2 files changed, 6 insertions(+), 3 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_1-4-0-625-g0b94fe8f
by Richard B. Kreckel 04 Apr '19

04 Apr '19

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 0b94fe8f8567e31268adede7c7ea671ef80a8558 (commit) from 3d962a6ef2acd92207cdfc164a33d13c5c827dc9 (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 0b94fe8f8567e31268adede7c7ea671ef80a8558 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Thu Apr 4 20:21:41 2019 +0200 Fix cl_N output of negative fixnums. Thanks to Feng Feng for reporting this. ----------------------------------------------------------------------- Summary of changes: ginac/numeric.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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