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GiNaC 1.8.7 released
by Richard B. Kreckel 12 Aug '23

12 Aug '23

Hi, GiNaC 1.8.7 has been released. Here're the news: * Fix series expansion of polynomial(x)^n for small and large n. Previously, this could return two Order terms or an Order term even though the series was terminating at a lower order. * Fix bugs in internal parser from strings. The operator precedence of the internal parser was inconsistent and has now been harmonized with that of ginsh. * Make ginsh evaluate line-by-line in non-interactive mode. This helps programs invoking ginsh as a sub-program. * Several build fixes. Happy hacking! -richy. -- Richard B. Kreckel <https://in.terlu.de/~kreckel/>

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Floating to Rational
by Charles White 19 Jul '23

19 Jul '23

Hi GiNaC! Is there a way to convert floating point numbers to rational numbers? And, expressions with floating point numbers to expressions with rational numbers? wxmaxima has the function "rationalize"; I did notice there is a rationalize <https://www.ginac.de/CLN/cln.html#Conversion-to-rational-numbers> function in the CLN library; is that what I should work with? Thanks! Charles

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linking problem using Cygwin + cl compiler
by Piotr 26 Jun '23

26 Jun '23

Hello, I am trying to compile ginac and cln on Windows. For compilation I used Cygwin env, cl compiler (MSVC v142). Version I use: -cln 1.3.6 -ginac 1.8.6, but with this fix: I following this instruction mainly: https://ooo-imath.sourceforge.io/wiki/index.php/Compiling_under_Windows Cln is compiled successfully. For GINAC compilation I have some errors not desribed in instruction above: 1. ./configure required: /std:c++20 parameter as it is complaining during compilation 2. symbol differences that I am not able to solve. They are related to Cln: ginac.lib(libginac_la-numeric.obj) : error LNK2019: nierozpoznany symbol zewnętrzny "struct cln::cl_heap_string * __cdecl cl_make_heap_string(char const *)" (?cl_make_heap_string@@YAPEAUcl_heap_string@cln@@PEBD@Z) przywołany w funkcji "public: __cdecl cln::cl_string::cl_string(char const *)" (??0cl_string@cln@@QEAA@PEBD@Z) Wskazówki dla symboli, które są zdefiniowane i mogą potencjalnie pasować: "struct cln::cl_heap_string * __cdecl cln::cl_make_heap_string(char const *)" (?cl_make_heap_string@cln@@YAPEAUcl_heap_string@1@PEBD@Z) .libs\viewgar.exe : fatal error LNK1120: liczba nierozpoznanych elementów zewnętrznych: 1 It can be seen that both symbols differs only with class prefix at the beginning ::cln (it is in existing symbol in cln lib but not in looked one in ginac) Do anybody knows how to solve this link issue? Thank you in advance, Best regards, Piotr -- Ta wiadomość e-mail została sprawdzona pod kątem wirusów przez oprogramowanie antywirusowe Avast. www.avast.com

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Making ginsh interactive when the input is not a TTY
by Vitaly Magerya 21 Jun '23

21 Jun '23

Hi, all. I've been trying to use ginsh as a subprocess: send some input to it, have it evaluate it, read the result back, repeat. I've found that this is impossible: in ginsh/ginsh_lexer.lpp:161 if yy_is_interactive (=isatty(0)) is false, ginsh uses fread() to read the input, which means it will not stop after end of the line -- it will instead wait until the whole buffer is filled, and will only proceed to parse and evaluate afterwards. This means I can not send "1+2\n" and expect an answer, ginsh will wait for more input. This of course is unlike the interactive mode (yy_is_interactive == 1), where the input is read character-by-character until the end of line. So, basically, I'd like ginsh to use the interactive(-ish) mode even when the input stream is not a TTY. Now, just forcing yy_is_interactive to 1 will work, but is not a good solution: the interactive mode prints the prompt after each line, so using it when the input stream is not a TTY will break backward compatibility. Instead, something like this will work for me: diff --git a/ginsh/ginsh_lexer.lpp b/ginsh/ginsh_lexer.lpp index 8692b1ac..a8d571dd 100644 --- a/ginsh/ginsh_lexer.lpp +++ b/ginsh/ginsh_lexer.lpp @@ -203,9 +203,16 @@ static int ginsh_input(char *buf, int max_size) YY_FATAL_ERROR("input in flex scanner failed"); result = n; #endif - } else if (((result = fread(buf, 1, max_size, yyin)) == 0) && ferror(yyin)) - YY_FATAL_ERROR("input in flex scanner failed"); - + } else { + int c = '*', n; + for (n = 0; n < max_size && (c = getc(yyin)) != EOF && c != '\n'; ++n) + buf[n] = (char)c; + if (c == '\n') + buf[n++] = (char)c; + if (c == EOF && ferror(yyin)) + YY_FATAL_ERROR("input in flex scanner failed"); + result = n; + } return result; } This will preserve backward compatibility. There is however a concern that such a change will affect the parsing performance, so I've run tests: when evaluating some of my multi-MB expression files with mixed arithmetic, there is no statistically visible performance difference. For a synthetic test of a product of 10^6 of single-digit numbers with 6 white-space characters per digit per -- no change. For a sum of 10^6 single-digit integers with 6 spaces per integer I see a 9% runtime regression; if the whitespace is removed, the regression disappears. In short, I think the performance impact in practice is zero. Can I ask for this change to be applied?

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Re: [GiNaC-list] GiNaC::parser parses unary operators in the wrong order
by Vitaly Magerya 20 Jun '23

20 Jun '23

On 20/02/2023, I wrote: > Hi, all. When parsing expressions with sign in the exponent, GiNaC's > parses confuses the priorities somehow. Here are some examples: > > 3^2+1 is parsed as (3^2)+1, which is correct; > 3^+2+1 is parsed as 3^(+2+1), which is wrong; > 3^-2+1 is parsed as 3^(-2+1), which is wrong; > 3^+2/3 is parsed as 3^(+2/3), which is wrong; > etc. So after some more testing I found that GiNaC doesn't only misparse the exponentiation this way, but multiplication too. Things like "3*+2+1" are parsed wrong too. The handling of the unary operators is broken if they appear after other operators. As a separate problem, parsing nested exponentiation, like "2^3^4", results in GiNaC throwing an exception, saying that "power should have exactly 2 operands", which is false: for example ginsh handles "2^3^4" easily and correctly. So, with some work I was able to fix both of these problems. I'm attaching a proposed solution, with tests included. Would it be possible to commit this? I would additionally like to request a point release after this fix; this parsing problem potentially affects our usage of GiNaC, and we'd rather stay with a release version than build our own release tarballs.

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Any way to get the leading order of a series expansion?
by Vitaly Magerya 16 May '23

16 May '23

Hi, all. We have some code needs to have the first N orders of a series expansion of an expression; so far we've been actually using sympy for this: there one can use series() [1] directly, as it computes "the first N orders", whereas in GiNaC series() expands "up to N-th order", so if I just need e.g. the leading order, then series() can't help me directly. Any idea of how can one get the leading order, or the first N orders with GiNaC? Would this need a lot of effort to implement? [1] https://docs.sympy.org/latest/modules/series/series.html#sympy.series.serie…

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Polynomial Factoring
by Charles White 05 May '23

05 May '23

Hi GiNaC! I love the library! Keep up the good work! Currently I am trying to find exact eigenvalues. My solution so far is to factor the characteristic equation then I can try to find roots of the factored polynomials. But, I need a list of expressions that store the factored polynomials. For example in the ginsh I have: ``` > rat = pow(x,6)+1; 1+x^6 > factor(rat); (1+x^4-x^2)*(1+x^2) ``` Then I need a list with the expressions (1+x^4-x^2) and (1+x^2); from there I can calculate the roots exactly. Is this possible? Is there a better way to find exact eigenvalues? Thanks! Charles

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How to express and simplify symbolic expressions in Ginac?
by Anubhavnidhi Abhashkumar . 20 Apr '23

20 Apr '23

Hi, I am pretty new to GiNac library in c++ and am struggling with one particular topic. I have been using ginac-1.8.6 I want to represent and simplify symbolic expressions (expressions with union, intersection, and not operator) with GiNac. I have been trying the following example #include <iostream>#include <ginac/ginac.h>using namespace std;using namespace GiNaC; int main(){ symbol x("x"), y("y"), z("z"); ex boolean_expr = (!x || y) && (x || z); cout << "Boolean expression: " << boolean_expr << endl; ex simplified_expr = normal(boolean_expr); cout << "Simplified expression: " << simplified_expr << endl; return 0; } But I keep on getting errors related to ||, !, and && operators. For example, > note: candidate: ‘operator!(bool)’ <built-in> > note: no known conversion for argument 1 from ‘GiNaC::symbol’ to `bool’ > error: no match for ‘operator!’ (operand type is `GiNaC::symbol’) I also tried replacing ||, !, and && to or, not, and, respectively but get similar errors > error: no match for ‘operator!’ (operand type is ‘GiNaC::symbol’) ex boolean_expr = not(x) or y and (x or not(z)); So my question is how can I represent and, or, not. I am using Ginac 1.8.6 from here <https://www.ginac.de/Download.html>. I also checked the manual here <https://www.ginac.de/tutorial.pdf> but did not find an answer. Thanks, Archie http://anubhavnidhi.github.io/

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LaTeX Output
by Charles White 18 Apr '23

18 Apr '23

Hi GiNaC! I love the library! Keep up the good work! Currently though I am having trouble with LaTeX output; I would like to parse an expression, then set the LaTeX name to the symbols that were generated from the reader. I can do that, but the expression doesn't change when I print it. Here is an minimal example: #include <ginac/ginac.h> std::string addTeXbrackets(std::string const& in) { std::string ret = in; std::string::size_type pos = 0; while((pos = ret.find('_', pos)) != std::string::npos) { ret.replace(pos, 1, "_{"); pos += 1; // move past the dot (and the extra '\n') ret.push_back('}'); } return ret; } int main(){ GiNaC::parser reader; GiNaC::ex e = reader("2*x_1+sin(y_2)"); GiNaC::symtab & vars = reader.get_syms(); std::cout << GiNaC::latex; for (std::pair<std::string, GiNaC::ex> var : vars) { // loop through each symbol then texify and use "set_TeX_name()" GiNaC::ex_to<GiNaC::symbol &>(var.second).set_TeX_name(addTeXbrackets(var.first)); std::cout<<var.second<<std::endl; } //<- Not sure how to add latex to the output yet std::cout<<e<<std::endl; } //output is: x_{1} y_{2} 2 x_1+\sin(y_2) Thanks! Charles

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feature request
by Marko Riedel 22 Feb '23

22 Feb '23

Greetings to all. Continuing with my GiNaC project I have noticed that there was some functionality missing that other software offers. In particular, I require **factorization of integers** and a function to compute the **set of divisors** of an integer. I have implemented these using basic math such as might be used in a freshman course. It passes all my tests, but it really needs an implementation from a professional mathematician. Maybe you can file this with other feature requests you have received. An excerpt from my code follows below. I hope I have understood lists correctly that they are doubly linked and a list append of one element runs in constant time. Best regards, Marko lst factorizeposint(numeric n) { lst result = {}, ent; int pot = 0; while(irem(n, numeric(2)).is_zero()){ pot++; n = iquo(n, numeric(2)); } if(pot > 0){ ent = {numeric(2), pot}; result.append(ent); } numeric q = 3; while(q*q <= n){ pot = 0; while(irem(n, q).is_zero()){ pot++; n = iquo(n, q); } if(pot > 0){ ent = {q, pot}; result.append(ent); } q += 2; } if(n > 1){ ent = {n, numeric(1)}; result.append(ent); } return result; } numeric totient(numeric n) { if(n==1) return 1; lst pfact = factorizeposint(n); numeric result = n; for(lst::const_iterator it = pfact.begin(); it != pfact.end(); ++it){ lst ent = ex_to<lst>(*it); result *= numeric(1) -numeric(1)/ex_to<numeric>(ent.op(0)); } return result; } lst divisors(numeric n) { if (n==1) return {1}; lst pfact = factorizeposint(n), ent; numeric tau(1); lst::const_iterator it; for(it = pfact.begin(); it != pfact.end(); ++it){ ent = ex_to<lst>(*it); tau *= numeric(1)+ex_to<numeric>(ent.op(1)); } exvector res {}; res.resize(tau.to_int(), numeric(1)); int sofar = 1; int pos; for(it = pfact.begin(); it != pfact.end(); ++it){ pos = sofar; ent = ex_to<lst>(*it); numeric p = ex_to<numeric>(ent.op(0)); numeric v = ex_to<numeric>(ent.op(1)); for(numeric vv(1); vv <= v; vv++){ for(int q = 0; q < sofar; q++){ res[pos++] = res[q]*pow(p,vv); } } sofar = pos; } lst result = {}; for(pos=0; pos<sofar; pos++) result.append(res[pos]); return result; }

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