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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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GiNaC release 1.5.6
by Jens Vollinga 28 Jan '10

28 Jan '10

Hi everybody, GiNaC 1.5.6 is out and available. The changes are: * Fixed compile problem with gcc 3.4. * Improved excompiler: The ginac-excompiler script will only be installed if excompiler is supported and enabled. As always, this release can be downloaded from http://www.ginac.de/Download.html Best wishes, Jens

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parsing of declared functions with ginac 1.5
by Tony Stoecker 11 Dec '09

11 Dec '09

Hi All: I am happily using GiNaC since version 1.3. With version 1.5 I have the problem that parsing of declared functions does not work anymore (the way I am using it). The stupid example below works fine with version 1.4 but fails with version 1.5: terminate called after throwing an instance of 'GiNaC::parse_error' what(): GiNaC: parse error at line 0, column 0: no function "floor" with 1 arguments [GiNaC::ex GiNaC::parser::parse_identifier_expr()(parser/parser.cpp:66)] Did I miss something in the declaration to introduce the new function to the parser? Any help would be very much appreciated as I could not find the answer in the tutorial / mailing list. Cheers, Tony #include "ginac/ginac.h" static GiNaC::ex floor_evalf(const GiNaC::ex &x){ if (!GiNaC::is_a<GiNaC::numeric>(x) ) return x; GiNaC::ex xn = GiNaC::ex_to<GiNaC::numeric>(x); return ((int) GiNaC::ex_to<GiNaC::numeric>(xn).to_double() ); } DECLARE_FUNCTION_1P(floor) REGISTER_FUNCTION(floor, evalf_func(floor_evalf)) using namespace std; using namespace GiNaC; int main() { symbol x("x"); lst syms; syms.append(x); lst nums; nums.append(1.9); //parsing from string does not work with version 1.5 ex p("floor(x)",syms); cout << syms << "=" << nums << " ; " << p << "=" << evalf(p.subs(syms,nums)) << endl; exit(0); } ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------ Forschungszentrum Juelich GmbH 52425 Juelich Sitz der Gesellschaft: Juelich Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498 Vorsitzende des Aufsichtsrats: MinDir'in Baerbel Brumme-Bothe Geschaeftsfuehrung: Prof. Dr. Achim Bachem (Vorsitzender), Dr. Ulrich Krafft (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt, Prof. Dr. Sebastian M. Schmidt ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------

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Substitution of indexed expressions
by Z S 16 Nov '09

16 Nov '09

I am new to ginac, and I want to simplify some expected values of indexed expressions. As a toy example, I wanted to simplify E[\sum_{i,j} A.i.j ^ 2] where it is known that E[A.i.j * A.i.j] = 1. The answer should be N + E[ \sum{i,j} A.i.j \sum_{k != i,l != j} A.k.l]. I tried to use the following program but it doesnt work. Any help would be greatly appreciated as I need to implement similar but more involved expressions. Thanks! #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main() { symbol N("N"); symbol i_sym("i"), j_sym("j"); idx i(i_sym, N), j(j_sym, N); symbol A("A"); ex e = indexed(A,i,j) * indexed(A,i,j); cout << "e = "<< e<< endl; cout << "Free indices = " << exprseq(e.get_free_indices()) << "\n"; // I want to substitute A.i.j * A.i.j = 1, for any i,j // The following gives a run time error //ex e3 = subs(e,indexed(A,wild(),wild()) * indexed(A,wild(),wild()) == 1); // The following doesnt substitute/simplify anything idx i0(wild(),N), i1(wild(),N); ex e3 = subs(e,indexed(A,i0,i1) * indexed(A,i0,i1) == 1); cout << "e3 = " << e3 << endl; cout << "Free indices = " << exprseq(e3.get_free_indices()) << "\n"; }

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GiNaC release 1.5.5
by Jens Vollinga 04 Nov '09

04 Nov '09

Hi everybody, the last release, 1.5.4, didn't have the correct library versioning. This release fixes the problem. GiNaC 1.5.5 is out and available. The changes are: * Correct libtool versioning. As always, this release can be downloaded from http://www.ginac.de/Download.html Best wishes, Jens

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Release GiNaC 1.5.4
by Jens Vollinga 02 Nov '09

02 Nov '09

Hi everybody, GiNaC 1.5.4 is out and available. The changes are: * Default parser now can again read in user defined classes. * Add mul::info() and add::info() support for numeric info_flags (GiNaC now can detect that the sum or product of a number of positive expressions is again a positive expression). * Fixed cast that caused compile error on 64bit machines. * Fixed incorrect uses of STL iterators. * Removed subdirectory debian. * Output LaTeX-symbols using \mathrm, instead of \mbox. As always, this release can be downloaded from http://www.ginac.de/Download.html Best wishes, Jens

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