September 2019 - GiNaC-devel

pseries::evalf() and pseries::eval()
by Vladimir V. Kisil 02 Oct '19

02 Oct '19

Dear All, GiNaC tutorial in section "2.2 What it can do for you" says that Ginsh shall produce: > series(tgamma(x),x==0,3); x^(-1)-Euler+(1/12*Pi^2+1/2*Euler^2)*x+ (-1/3*zeta(3)-1/12*Pi^2*Euler-1/6*Euler^3)*x^2+Order(x^3) > evalf(%); x^(-1)-0.5772156649015328606+(0.9890559953279725555)*x -(0.90747907608088628905)*x^2+Order(x^3) However, with the current GiNaC versions the second output will be identical to the first. I am attaching a small patch which shall restore the expected output. Best wishes, Vladimir -- Vladimir V. Kisil http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Transformations http://goo.gl/EaG2Vu Software: Geometry of cycles http://moebinv.sourceforge.net/ Jupyter (Colab): https://github.com/vvkisil/MoebInv-notebooks Jupyter (CodeOcean): https://codeocean.com/capsule/7952650/tree

2 2

[SCM] GiNaC -- a C++ library for symbolic computations tag, release_1-7-7, created. release_1-4-0-640-gd3ed1010
by Richard B. Kreckel 23 Sep '19

23 Sep '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_1-7-7 has been created at d3ed10100d250016e9fd0bcf24f221ea2be759fa (commit) - Log ----------------------------------------------------------------- commit d3ed10100d250016e9fd0bcf24f221ea2be759fa Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Sep 22 23:50:45 2019 +0200 Really finalize 1.7.7 release. ----------------------------------------------------------------------- hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

1 0

Release 1.7.7
by Richard B. Kreckel 22 Sep '19

22 Sep '19

Hi, GiNaC 1.7.7 has just been released. It fixes some bugs (see NEWS) and depends on Python3 for build (this may be important for distros). Happy hacking! -richy. -- Richard B. Kreckel <https://in.terlu.de/~kreckel/>

1 0

[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-640-gd3ed1010
by Richard B. Kreckel 22 Sep '19

22 Sep '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 d3ed10100d250016e9fd0bcf24f221ea2be759fa (commit) from e9d15a5eb2279f4c9b153af3dbb487843cc9c048 (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 d3ed10100d250016e9fd0bcf24f221ea2be759fa Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Sep 22 23:50:45 2019 +0200 Really finalize 1.7.7 release. ----------------------------------------------------------------------- Summary of changes: NEWS | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

1 0

[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-639-ge9d15a5e
by Richard B. Kreckel 22 Sep '19

22 Sep '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 e9d15a5eb2279f4c9b153af3dbb487843cc9c048 (commit) via 070c40317a57a1f9918a079f1adeecd5a1ac155a (commit) from 9f3e78a13c72ca73ade4d0829186edcdc1c1b2a0 (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 e9d15a5eb2279f4c9b153af3dbb487843cc9c048 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Sep 22 23:39:06 2019 +0200 Finalize 1.7.7 release. commit 070c40317a57a1f9918a079f1adeecd5a1ac155a Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Sep 22 23:32:14 2019 +0200 Replace some .push_back() with .emplace_back() where it's safe. ----------------------------------------------------------------------- Summary of changes: NEWS | 5 +++++ ginac/archive.cpp | 12 +++++------ ginac/power.cpp | 26 +++++++++++----------- ginac/pseries.cpp | 64 +++++++++++++++++++++++++++---------------------------- ginac/version.h | 4 ++-- 5 files changed, 58 insertions(+), 53 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

1 0

Archiving an empty container
by Vladimir V. Kisil 22 Sep '19

22 Sep '19

Dear All, There is an issue with GiNaC archiving an empty container. This is illustrated by the code included below. The archived empty list z is read in the expression z1 as a list with one element. Also such code can crashes id an empty container is archived first. The reason is in lines 215-216 of container.h: here GiNaC got first=last for both: empty containers and containers with one element. I propose the attached patch, which modifies the return value of archive_node::find_last() (called at line 216 of container.h) by 1. All other calls of archive_node::find_last() are revised to agree with the change. Best wishes, Vladimir -- Vladimir V. Kisil http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Transformations http://goo.gl/EaG2Vu Software: Geometry of cycles http://moebinv.sourceforge.net/ Jupyter (Colab): https://github.com/vvkisil/MoebInv-notebooks Jupyter (CodeOcean): http://doi.org/10.24433/CO.9934595.v2 ====================================== #include <iostream> #include <fstream> #include <stdexcept> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main(int argc, char** argv) { ex x = lst{1,2}, y = lst{3}, z = lst{}; GiNaC::archive A; A.archive_ex(x, "2elem"); A.archive_ex(y, "1elem"); A.archive_ex(z, "empty"); ofstream out("/tmp/test.gar", ios::binary); out << A; out.flush(); out.close(); GiNaC::archive A1; std::ifstream ifs("/tmp/test.gar", std::ifstream::in | ios::binary); ifs >> A1; ex x1 = A1.unarchive_ex(lst{}, "2elem") ; ex y1 = A1.unarchive_ex(lst{}, "1elem") ; ex z1 = A1.unarchive_ex(lst{}, "empty") ; x1.dbgprint(); // -> {1,2} y1.dbgprint(); // -> {3} z1.dbgprint(); // -> {1} return 0; }

2 5

[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-637-g9f3e78a1
by Richard B. Kreckel 22 Sep '19

22 Sep '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 9f3e78a13c72ca73ade4d0829186edcdc1c1b2a0 (commit) via 67a2e95e20ac5354755993ba567f504718b74594 (commit) from fe3af74fb8c8af4c8ab008c4788a7755b602db08 (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 9f3e78a13c72ca73ade4d0829186edcdc1c1b2a0 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Sep 22 19:18:19 2019 +0200 Fix unarchiving empty containers. The bug was reported by Vladimir V. Kisil <kisilv(a)maths.leeds.ac.uk>, see <https://www.ginac.de/pipermail/ginac-devel/2019-September/002399.html>. commit 67a2e95e20ac5354755993ba567f504718b74594 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Sep 22 19:02:31 2019 +0200 Update m4/ax_cxx_compile_stdcxx.m4 to current upstream version. ----------------------------------------------------------------------- Summary of changes: ginac/archive.cpp | 30 +++++++++++++++++++++++------- ginac/archive.h | 18 +++++++++++++----- ginac/container.h | 10 ++++------ ginac/expairseq.cpp | 10 ++++------ ginac/matrix.cpp | 8 +++----- ginac/pseries.cpp | 10 ++++------ m4/ax_cxx_compile_stdcxx.m4 | 5 ++++- 7 files changed, 55 insertions(+), 36 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

1 0

[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-635-gfe3af74f
by Richard B. Kreckel 22 Sep '19

22 Sep '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 fe3af74fb8c8af4c8ab008c4788a7755b602db08 (commit) from 452e51c8a3b84c368ae3ba2e60dacbc1985e7b5c (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 fe3af74fb8c8af4c8ab008c4788a7755b602db08 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Sep 22 13:19:00 2019 +0200 Remove exhashmap<T> class. Class exhashmap<T> was a workaround for missing std::hash_map<Key, T> in the original C++98 standard. It was put in GiNaC because map<Key, T> was deemed too slow. Since C++11 there is std::unorderd_map<Key, T>, which is hash-based. To be able to use it, add specializations of std::hash<ex> and std:equal_to<ex>. ----------------------------------------------------------------------- Summary of changes: check/CMakeLists.txt | 2 - check/Makefile.am | 8 - check/exam_hashmap.cpp | 293 ------------------------- check/time_hashmap.cpp | 117 ---------- doc/tutorial/ginac.texi | 41 +--- ginac/ex.h | 20 ++ ginac/hash_map.h | 570 +----------------------------------------------- 7 files changed, 28 insertions(+), 1023 deletions(-) delete mode 100644 check/exam_hashmap.cpp delete mode 100644 check/time_hashmap.cpp hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

1 0

Erasing-inserting exhashmap
by Vladimir V. Kisil 22 Sep '19

22 Sep '19

Dear All, I have an issue with exhashmap, namely repeated erasing-insertion of elements eventually become trapped in an infinite loop in lines 487-491 of hash_map.h. Here is a sample code: #include <ginac/ginac.h> using namespace GiNaC; int main() { exhashmap<ex> M; M[realsymbol("x")] =1; int N= 30; for (int i =0; i < N; ++i ) { realsymbol a("a"); M[a]=numeric(i); M.erase(a); } return 0; } With this value of N the infinite loop appears on my computer with a probability around 40%. With larger values of N an infinite loop is almost certain. Did I miss something? Best wishes, Vladimir PS Also just to check that my patch for archiving empty lists from Sep 10 is not lost. -- Vladimir V. Kisil http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Transformations http://goo.gl/EaG2Vu Software: Geometry of cycles http://moebinv.sourceforge.net/ Jupyter (Colab): https://github.com/vvkisil/MoebInv-notebooks Jupyter (CodeOcean): http://doi.org/10.24433/CO.9934595.v3

2 2

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.

2 2