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Given a formal iterated derivative (GiNaC::fderivative), what actually is it?
by Ricardo Buring 14 Apr '16

14 Apr '16

Dear list, Using GiNaC one can define a symbolic/formal function f of two variables as follows: DECLARE_FUNCTION_2P(f) REGISTER_FUNCTION(f, dummy()) Formal derivatives can be computed by defining symbols x, y and calculating e.g. f(x,y).diff(x, 3).diff(y, 2) which is printed as D[0,0,0,1,1](f)(x,y) This is fantastic. Now, I would like to obtain the list [0, 0, 0, 1, 1] from the above expression. Checking the printing code GiNaC::fderivative::do_print, this is stored in a GiNaC::paramset. However, it's protected, and it doesn't seem to be accessible by any method. My attempt if (is_a<fderivative>(e)) { fderivative fder = ex_to<fderivative>(e); for (auto x : fder.parameter_set) cout << x << ", "; } therefore fails. Could an accessor or some such be implemented so this (basic) operation becomes possible? Best regards, Ricardo

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Release 1.6.7
by Richard B. Kreckel 29 Feb '16

29 Feb '16

Hi, A new GiNaC release is out and available. It fixes two elusive bugs in sqrfree() and normal(), which indirectly also affect numer() and denom(). Happy hacking -richy. -- Richard B. Kreckel <http://in.terlu.de/~kreckel/>

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Re: [GiNaC-list] erf()
by Vladimir V. Kisil 26 Feb '16

26 Feb '16

>> Vincent Huber vincent.huber at cemosis.fr VH> Is there a *Ginac* way to compute the erf() function ? At present, I do not see any other ways but: 1. Use some external library (GSL?) to evaluate numerical values of the function. 2. Write user-defined function if any symbolic properties are required. -- 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/

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erf()
by Vincent Huber 24 Feb '16

24 Feb '16

Dear members, Is there a *Ginac* way to compute the erf() function ? All the best, VH -- Docteur Ingénieur de recherche CeMoSiS <http://www.cemosis.fr> - vincent.huber(a)cemosis.fr Tel: +33 (0)3 68 8*5 02 06* IRMA - 7, rue René Descartes 67 000 Strasbourg

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Possible bug in sqrfree
by Diego Conti 03 Feb '16

03 Feb '16

Hi, if I understand correctly, the preconditions of sqrfree do not require the operand to be in expanded form. However, invoking it on some non-expanded polynomials results in a division-by-zero error on my system (code attached). Is this a bug in sqrfree? I am using gcc 5.1.1 and GiNaC 1.6.6. Diego

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Namespace error with is_ex_the_function
by Jacob Garber 20 Oct '15

20 Oct '15

Hello, The following program #include <iostream> #include <ginac/ginac.h> int main() { GiNaC::symbol x("x"); std::cout << GiNaC::is_ex_the_function(x, GiNaC::sin) << std::endl; } gives me a compilation error: bug.cpp:6:24: error: unexpected parenthesis after '::' std::cout << GiNaC::is_ex_the_function(x, GiNaC::sin) << std::endl; ^ /usr/local/include/ginac/function.h:767:43: note: expanded from macro 'is_ex_the_function' #define is_ex_the_function(OBJ, FUNCNAME) (GiNaC::is_the_function<FUNCNAME##_SERIAL>(OBJ)) ^ bug.cpp:6:17: error: no member named 'GiNaC' in namespace 'GiNaC'; did you mean simply 'GiNaC'? std::cout << GiNaC::is_ex_the_function(x, GiNaC::sin) << std::endl; ^ /usr/local/include/ginac/parser.h:31:11: note: 'GiNaC' declared here namespace GiNaC { ^ bug.cpp:6:24: error: expected ';' after expression std::cout << GiNaC::is_ex_the_function(x, GiNaC::sin) << std::endl; ^ /usr/local/include/ginac/function.h:767:90: note: expanded from macro 'is_ex_the_function' #define is_ex_the_function(OBJ, FUNCNAME) (GiNaC::is_the_function<FUNCNAME##_SERIAL>(OBJ)) ^ bug.cpp:6:24: error: expected expression /usr/local/include/ginac/function.h:767:90: note: expanded from macro 'is_ex_the_function' #define is_ex_the_function(OBJ, FUNCNAME) (GiNaC::is_the_function<FUNCNAME##_SERIAL>(OBJ)) ^ 4 errors generated. This is with GiNaC 1.6.5 on Mac OS 10.11, with compiler Apple version 7.0.0. It seems there is an issue with the namespace. Removing `GiNaC::` from `is_ex_the_function` compiles fine. Anyone else have this? Cheers, Jacob Garber

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Linking dl libraries is missing in ginac.pc
by Isuru Fernando 17 Sep '15

17 Sep '15

Hi, 5745deb8 introduced linking with dl libraries, but it was not added to the .pc files. Therefore list of link flags given by pkg-config is incomplete and fails if `-ldl` is not added manually. I have attached a patch which uses CMAKE_DL_LIBS variable ( http://www.cmake.org/cmake/help/cmake2.6docs.html#variable:CMAKE_DL_LIBS) Thanks, Isuru Fernando

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Typo in the documentation
by Jean-Michaël Celerier 01 Aug '15

01 Aug '15

Hello, In the html doc, section 5.15.2 I think that : { parser reader; ex e = reader("2*x+sin(y)"); symtab table = reader.get_syms(); symbol x = reader["x"]; symbol y = reader["y"]; } the two last lines should be symbol x = table["x"]; symbol y = table["y"]; Best regards Jean-Michaël Celerier

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Release 1.6.5
by Richard B. Kreckel 27 Jul '15

27 Jul '15

Hi, A new GiNaC release is out and available. These are the changes: * Fix pow(+(...),2).expand() where the sum contained roots of expressions. * Speed-up pow(+(...),n).expand() where n > 3. * Fix a crash in PolyLogs of rational numbers. Happy hacking -richy. -- Richard B. Kreckel <http://in.terlu.de/~kreckel/>

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Goncharov polylog. leads to Segmentation Fault
by Alexander Hasselhuhn 27 Jul '15

27 Jul '15

Dear all, when trying to evaluate G(I,sqrt(2)) I get "Segmentation fault", both in ginsh as well as in a program: --- begin code --- #include <ginac/ginac.h> using namespace GiNaC; int main () { ex two = 2; ex res = G (lst (I), sqrt(two)); return 0; } --- end code --- Not sure whether this is a different issue, but if instead use try to evaluate G(I,1/sqrt(2)), I get the error-message from cln: --- begin output --- terminate called after throwing an instance of 'cln::notreached_exception' what(): Internal error: statement in file float/conv/cl_F_from_RA.cc, line 27 has been reached!! Please send the authors of the program a description how you produced this error! Aborted --- end output --- I'm using GiNaC v1.6.4 with cln v1.3.3 on OpenSuse 13.2. I compiled GiNaC with gcc v4.8.3. Does this happen on other machines also? Yours, Alex

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