- GiNaC-list - ginac.de

Can GiNaC set info_flag?
by Seungyun Cho 19 May '10

19 May '10

For example, I want to set a symbol r to be rational, or real, but without specifying a value. I know one can use info(info_flags::real) to determine if an object is real, but I want to do the opposite. I found a type 'realsymbol' to do this, but I want many other scopes such as rational, prime, positive integer, pure imaginary, etc. Is there any solution?

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[PATCH] found a memory leak in /ginac/excompiler.cpp
by Martin Ettl 17 May '10

17 May '10

Hello, during a longer debugging session i identified a memory leak in ginac/excompiler.cpp at line 116 and 121. Please refer the attached patch that fixes the issue. Best regards Ettl Martin -- GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT! Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01

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conjugates of power objects
by Burcin Erocal 06 May '10

06 May '10

On Mon, 26 Apr 2010 18:02:40 -0700 (PDT) kcrisman <kcrisman(a)gmail.com> wrote: > On Apr 26, 4:09 pm, John Cremona <john.crem...(a)gmail.com> wrote: > > This is certainly a bug: > > > > sage: a = sqrt(-3) > > sage: a > > sqrt(-3) > > sage: a.conjugate() > > sqrt(-3) > > > > sage: bool(a==a.conjugate()) > > True > > > > Yeah, this is bad, and according to a.conjugate?? it seems to be > something wrong with our Ginac/Pynac use. This is a bug in GiNaC: ginsh - GiNaC Interactive Shell (ginac V1.5.7) __, _______ Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, (__) * | Germany. This is free software with ABSOLUTELY NO WARRANTY. ._) i N a C | You are welcome to redistribute it under certain conditions. <-------------' For details type `warranty;'. Type ?? for a list of help topics. > sqrt(-3); sqrt(-3) > conjugate(sqrt(-3)); sqrt(-3) For conjugation, power objects just compute the conjugate of the basis and the exponent, and construct a new power object from these. Here is the relevant function: http://pynac.sagemath.org/hg/file/3ece9ba22005/ginac/power.cpp#l805 Cheers, Burcin

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Inconsistent output, with integration.
by Akshay Srinivasan 13 Apr '10

13 Apr '10

Hello, I recently wrote a simple program to generate legendre polynomials of a given degree n. Thing though is that although the program is working perfectly in principle, the output thrown out by the program is not the same everytime I run it. The signs of the coefficient change between executions; it doesn't seem to follow any pattern either. I couldn't really figure out why this happens. Can someone throw more light on this ? Akshay -------------------------------------------------------------------- Bash Session: [neptune ~/devel/cpp] ./legendre 3 L(3) == 35/8*sqrt(8/175)*(5*x^3-3*x) [neptune ~/devel/cpp] ./legendre 3 L(3) == -35/8*(3*x-5*x^3)*sqrt(8/175) [neptune ~/devel/cpp] ./legendre 3 L(3) == 35/8*(5*x^3-3*x)*sqrt(8/175) [neptune ~/devel/cpp] ./legendre 3 L(3) == 35/8*sqrt(8/175)*(5*x^3-3*x) [neptune ~/devel/cpp] ./legendre 3 L(3) == -35/8*sqrt(8/175)*(3*x-5*x^3) [neptune ~/devel/cpp] ------------------------------------------------------------------ My program: #include<iostream> #include<ginac/ginac.h> using namespace std; using namespace GiNaC; ex inner(ex a, ex b, symbol &x){ return integral(x, -1, 1, a*b).eval_integ(); } ex legendre(unsigned int n, symbol &x){ ex lp, t; lp = pow(x, n); if(n != 0){ for(int i = 0; i < n; i++){ t = legendre(i, x); lp = lp - inner(lp, t, x) * t; } } lp = lp / sqrt(inner(lp, lp, x)); return lp; } int main(int argc, char *argv[]){ symbol x("x"); int n; ex lp, ln; n = atoi(argv[1]); lp = legendre(n, x); cout << "L(" << n << ") == " << lp << endl; return 0; } -------------------------------------------------------------------------------

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GiNaC release 1.5.7
by Jens Vollinga 29 Mar '10

29 Mar '10

Hi everybody, GiNaC 1.5.7 is out and available. The changes are: * Fixed a bug in the GCD code (infinite loop in pgcd()). * Fixed a bug in atan2() (division by zero error for atan2(x,0) if x is a negative and composite term). * Products now correctly set info_flags::negative and info_flags::negint. As always, this release can be downloaded from http://www.ginac.de/Download.html Best wishes, Jens

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How to pass an array of expressions as argument to a wrapped function?
by Kris&EJ Pol 27 Mar '10

27 Mar '10

Hello, This is a question from a relative newbie in GiNaC. I'm running GiNaC 1.5, and have been able to wrap some of my own simple functions with the DECLARE and REGISTER macros. This works very smoothly. Great! However, now I want to make a next step, and I don't know how to proceed. The next new home-made function should take an array of expressions as an argument. Inside the new function, the array needs to be indexed by a second parameter to the new function. The new function is an interpolating function. I have tried regular arrays, lst, and matrix, but I can't find a way to pass the expression array to the evalf function, in such a way that it can be indexed by a second expression argument. Is it correct that indexing of a lst by an expression is not supported in ginac? Which approach would you recommend to construct an interpolating function, taking an array of expressions to be interpolated, and an expression as interpolation value? Can you give me an example evalf function declaration? Thanks in advance! Evert-Jan

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Extension to Boolean Algebra?
by Goran Frehse 25 Mar '10

25 Mar '10

Hi, Is there an extension of GiNAC to a boolean algebra? The "relational" class seems to be already a step in this direction, as mathematically it could be evaluated to true or false. We would like to apply GiNaC in a context that involves boolean as well as real-valued expressions. It would be great if boolean expression could be represented, manipulated (expansion to CNF, DNF), and, if possible, parsed from a string. If this has not yet been done but is possible in principle, could we add this extension ourselves? Thanks in advance for any pointers on the subject. Best regards, Goran

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can ginac solve inequalities ?
by Frederic 25 Mar '10

25 Mar '10

Hi, I'm new here, I only test GiNaC to see how it can help me. What I've seen of it so far with is very nice, especially C++ objects (no need to parse strings). But I don't see how to solve inequalities : x+y < 0 lsolve tells me : terminate called after throwing an instance of 'std::invalid_argument' what(): lsolve(): 1st argument must be a list of equations it works just fine with real equalities (replaced the '<' by '==' ): x+y == 0 I use GiNaC 1.5.2 on a 64b ubuntu system. But I haven't seen anything related on newer version's changelog. can GiNaC solve inequalities ? If yes, how ?!? and if no, why ? is it planned ? thanks in advance for any input... Fred

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make (ginac)
by Hans-Jürgen Greif 27 Feb '10

27 Feb '10

Hello, I have tried to install last ginac (27.2.2010) on a intel mac os 10.6.2. Here is the last output from make( have generated last cln under gmp): . . . Making all in check make[1]: Nothing to be done for `all'. Making all in ginsh sed -n -f ./ginsh_fcn_help.sed <ginsh.1 >ginsh_fcn_help.h sed -n -f ./ginsh_op_help.sed <ginsh.1 >ginsh_op_help.h g++ -DHAVE_CONFIG_H -I. -I../config -I../ginac -I./../ginac -I../ginac -DIN_GINAC -I/usr/local/include -g -O2 -MT ginsh_parser.o -MD -MP -MF .deps/ginsh_parser.Tpo -c -o ginsh_parser.o ginsh_parser.cc ginsh_parser.cc: In function ‘int yyparse()’: ginsh_parser.cc:2169: warning: deprecated conversion from string constant to ‘char*’ ginsh_parser.cc:2284: warning: deprecated conversion from string constant to ‘char*’ mv -f .deps/ginsh_parser.Tpo .deps/ginsh_parser.Po g++ -DHAVE_CONFIG_H -I. -I../config -I../ginac -I./../ginac -I../ginac -DIN_GINAC -I/usr/local/include -g -O2 -MT ginsh_lexer.o -MD -MP -MF .deps/ginsh_lexer.Tpo -c -o ginsh_lexer.o ginsh_lexer.cc mv -f .deps/ginsh_lexer.Tpo .deps/ginsh_lexer.Po /bin/sh ../libtool --tag=CXX --mode=link g++ -g -O2 -o ginsh ginsh_parser.o ginsh_lexer.o ../ginac/libginac.la -L/usr/local/lib libtool: link: g++ -g -O2 -o .libs/ginsh ginsh_parser.o ginsh_lexer.o -Wl,-bind_at_load ../ginac/.libs/libginac.dylib -L/usr/local/lib -ldl Undefined symbols: "cln::cl_free_heap_object(cln::cl_heap*)", referenced from: f_integer_content(GiNaC::container<std::vector> const&)in ginsh_parser.o f_integer_content(GiNaC::container<std::vector> const&)in ginsh_parser.o f_fsolve(GiNaC::container<std::vector> const&)in ginsh_parser.o f_fsolve(GiNaC::container<std::vector> const&)in ginsh_parser.o yylex() in ginsh_lexer.o yylex() in ginsh_lexer.0 Regards, gre

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Sage days 24 @ RISC, Austria
by Burcin Erocal 26 Feb '10

26 Feb '10

Hi, Sage days 24 will take place at RISC, in Austria this summer. You can find the announcement text below. As you may know, Sage uses a variant of GiNaC called pynac [1], which replaces the numeric class to use Python objects instead of cln, as its symbolic backend. [1] http://pynac.sagemath.org/ It would be great to see GiNaC developers & users at this event. There will be plenty of occasions for discussions and coding sessions. Feel free to write to me off list with any questions. Cheers, Burcin Feel free to distribute as appropriate. Apologies for multiple copies. ************************************************************ Sage Days 24 on Differential Algebra and Special Functions July 17-22, 2010 http://wiki.sagemath.org/days24 Research Institute for Symbolic Computation, Linz, Austria ************************************************************ The objective of this workshop is to * provide a gentle introduction to Sage (installation, features, tutorials on basic usage and development), and * bring differential algebra, special functions and symbolic computation communities together, to improve the facilities provided by Sage to support research in these fields. PLENARY SPEAKERS ---------------- * Peter Paule (RISC, Austria) * Alban Quadrat (INRIA Sophia Antipolis, France) * William Stein (University of Washington, USA) * Nico Temme (CWI, The Netherlands) * Felix Ulmer (IRMAR, France) The workshop will feature mathematical talks, presentations on Sage and coding sprints. It will be accessible to researchers at all levels, even those without any experience with Sage. ABOUT SAGE ---------- Sage is a free open-source mathematics software system licensed under the GPL. It combines the power of many existing open-source packages into a common Python-based interface. You will find more information about Sage on the website: http://www.sagemath.org Sage days have been wildly successful, helping to grow the developer community so that it is now the world's largest and most diverse open source mathematical software development effort. REGISTRATION ------------ There will be a registration fee of 40 Euros. Online registration will be available through the RISC Summer 2010 pages at the beginning of April 2010. You will also be able to book hotel rooms in Hagenberg during registration. Feel free to email the organizers beforehand if you intend to participate. You can also subscribe to the workshop mailing list for further announcements: http://groups.google.com/group/sagedays24 It is strongly recommended that participants bring their own laptop, as the number of on-site computers is limited. More information regarding this event is available at: http://wiki.sagemath.org/days24 We have some funding to offer support for accommodation and in limited cases travel expenses to participants from the European Community Member States (except Austria) and Associated States. A link to the application form is also available at the above website. Sincerely Yours, The organizing committee Burcin Erocal, Ralf Hemmecke and Temur Kutsia

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