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GiNaC 1.2.0 now available
by Christian Bauer 19 Mar '04

19 Mar '04

Hello! In an unforeseen turn of events, the GiNaC Group (who, by the way, don't endorse the use of recreational drugs, except for C++ templates and Pokemon movies) proudly presents GiNaC 1.2.0 "We don't have the funds for champagne but we're going to release anyway". (And we also finally leave CLN in the dust in terms of version numbers. Hah, in your face, Richy! :-) Compared to the last few 1.1.x releases, this one has a rather impressive list of changes, with the focus on improving GiNaC's extensibility: - Added a structure<T> template class for the easy creation of user-defined algebraic classes. - Added support for (acyclic) visitors, to allow cleaner implementations of algebraic algorithms. - Added a const_iterator class that can be used instead of op()/nops(). - Completely revamped the implementation of expression output. It is now possible to add new output formats, to change the behavior of predefined formats at run-time, and to have different output styles for algebraic functions. - Symbols can be made non-commutative. - Added a method ex::conjugate() and a function conjugate() for complex conjugation. Symbols can be declared as real or complex-valued. - Improved the speed of subs(), normal(), to_rational() and to_polynomial() by the use of maps instead of lists. The old forms subs(const lst & ls, const lst & lr, unsigned options) to_rational/to_polynomial(lst & repl) are still available for compatibility, but using the new forms subs(const exmap & m, unsigned options) to_rational/to_polynomial(exmap & repl) is more efficient, especially when the number of replacements is large. - quo(), rem(), prem(), sprem(), decomp_rational(), unit(), content(), primpart() and matrix::charpoly() now take a "const ex &" instead of a "const symbol &". - Redundant expressions (two ex pointing to different objects are found to be equal in compare()) are now actively deleted/fused to conserve memory and speed up subsequent comparisons. This behavior can be suppressed on a per-object level with status_flags::not_shareable. Lists and matrices are not shareable by default. - Lots of internal streamlining and optimizations. - Caveats for class implementors: - basic::copy() and basic::destroy() are gone; classes derived from basic can use the defaults for the assignment operator and copy constructor. [Roberto: this also means that annoying compiler warning is finally gone... :-] - basic::subs(), basic::normal(), basic::to_rational() and basic::to_polynomial() take 'exmap' objects instead of lists. - basic::subs() now descends into subexpressions (if accessible via nops()/op()/let_op()). If you have a custom implementation of subs() that calls basic::subs() after substituting subexpressions, this needs to be changed to a call to subs_one_level(). - lst::thislst() and exprseq::thisexprseq() renamed to thiscontainer(). - thiscontainer() and associated constructors now take a std::auto_ptr. - Overloading basic::print() is now deprecated. You should use print_func<>() class options instead. Most of the new features are explained in more detail in the tutorial. GiNaC 1.2.0 is not binary compatible to 1.1.x, so you have to recompile your stuff. It shouldn't be necessary to make any modifications to your sources when switching to 1.2, except when you implemented your own GiNaC classes (see above). As before, all 1.2.x releases will be (upwards) binary compatible to each other. There is a new CVS branch "ginac_1-2" for the 1.2.x series, and the CVS head branch will eventually become GiNaC 1.3 (or GiNaC 2.0, or GiNaC Advanced Datacenter Edition, or whatever). What's left to say? Ah, yes, download GiNaC 1.2.0 from ftp://ftpthep.physik.uni-mainz.de/pub/GiNaC Happy computing, Christian -- / Physics is an algorithm \/ http://www.uni-mainz.de/~bauec002/

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GiNaC 1.1.7 now available
by Christian Bauer 11 Mar '04

11 Mar '04

Hello! We're proud to present GiNaC release 1.1.7 "Legacy of Taylor" in which we: - Fixed a bug in canonicalize_clifford(). - Series expansion now works predictably. All terms with the exponent of the expansion variable smaller than the given order are calculated exactly. If the series is not terminating, the Order function is (at least) of the given order. Predictably, this release can be downloaded from ftp://ftpthep.physik.uni-mainz.de/pub/GiNaC/ Never stop coding, Christian -- / Physics is an algorithm \/ http://www.uni-mainz.de/~bauec002/

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differential operators
by Kai Ludwig 29 Feb '04

29 Feb '04

Hi All, I'm new to GiNac. Is there a way to execute symbolic differentiation of expressions that includes differential operators ? e.g. suppose an expression ex F = u * dx*u When differentiate that expression F.diff(u) it should result in the expression dx*u - u*dx Regards Kai -- http://echempp.sourceforge.net Kai Ludwig Universität Tübingen Institut für Organische Chemie Auf der Morgenstelle 18 D-72076 Tübingen Tel.: 07071/29-73049 Mail: kai.ludwig(a)uni-tuebingen.de

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Problems with order parameter of 'series' method
by Holger Eberle 19 Feb '04

19 Feb '04

Hello, when applying the 'series' method to an expression which only constists of adds, muls and pows, the final order of the expansion does not seem to depend pretictably on the parameter 'order' of 'series', e.g. symbol eps("eps"); ex expr = (pow(eps, 8)*pow(pow(eps,3)+ pow(eps + pow(eps,3), 2),-2)) .series(eps==0, 6); cout << "expr: " << expr << endl; produces "expr: Order(eps^2)" and not as expected (by me) "expr: 1*eps^4+(-2)*eps^5+Order(eps^6)" The first order parameter the expansion works correctly with again is 9, then I get an expansion up to Order(eps^13)... Does anyone know how to remedy that or at least how to handle series of this quite general type of expressions predictably? Thanks! Holger Eberle

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matrix in \frac{}{}
by Bodo Steiner 17 Feb '04

17 Feb '04

Hi, I'm trying to get this running, but it won't ... how can I have a matrix in the following formula: \begin{equation} \alpha^{\star}=\frac{\mbox{\boldmath$z$}^{T}\mbox{\boldmath$\Lambda$} \mbox{\boldmath$\Sigma$}}{\mbox{\boldmath$z$}^{T}\mbox{\boldmath$\Lambda$} \begin{bmatrix}-\mbox{\boldmath$K$}_{1}^{-1}&0\\ 0&\mbox{\boldmath$K$}_{2}^{-1} \end{bmatrix}\mbox{\boldmath$\Lambda$}^{T}\mbox{\boldmath$z$} +r\mbox{\boldmath$z$}^{T}\mbox{\boldmath$\Lambda$} \mbox{\boldmath$\Sigma$}\mbox{\boldmath$\Lambda$}^{T}{\mbox{\boldmath$z$}} \end{equation} thanks! -bodo.

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Fw: Question re Installing GiNaC
by Christian Bauer 28 Jan '04

28 Jan '04

Hi! Maybe someone with Cygwin experience can help here? ----- Forwarded message from Baruch Feldman <baruch_feldman(a)yahoo.com> ----- Dear Mr. Bauer, [...] I wanted to install GiNaC on my (windows) machine so that I could do calculations, etc. I haven't had a lot of experience with Gnu installations before. I basically downloaded both Cygwin and CLN in order to install GiNaC. The other two installations seemed to go OK, but with GiNaC I got the error message below. (I have no idea how to interpret this). Perhaps I put the files in the wrong place -- I wasn't sure where to put them so I put the GiNaC directory under lib. Do you know how to get around this problem? Thanks, Baruch Feldman In file included from /home/cbauer/projects/GiNaC-1.1/ginac/input_lexer.ll:35: input_lexer.h:43: error: conflicting types for `char ginac_yytext[]' input_lexer.cc:446: error: previous declaration as `char*ginac_yytext' input_lexer.h:43: error: storage size of `ginac_yytext' isn't known input_lexer.h:43: error: storage size of `ginac_yytext' isn't known make[2]: *** [input_lexer.lo] Error 1 make[2]: Leaving directory `/lib/GiNaC-1.1.6/ginac' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/lib/GiNaC-1.1.6' make: *** [all] Error 2 ----- End forwarded message ----- Bye, Christian -- / Physics is an algorithm \/ http://www.uni-mainz.de/~bauec002/

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STL algorithms and GiNaC::lst
by varg＠thsun1.jinr.ru 27 Jan '04

27 Jan '04

Hi! Here is a simple program: #include <iostream> #include <algorithm> #include <functional> #include <stdexcept> using namespace std; #include <ginac/ginac.h> using namespace GiNaC; class lst_prod { ex prod; public: lst_prod() : prod(ex(1)) { } lst_prod(const ex & init_) : prod(init_) { } void operator()(const ex & x) { cout << "We are called with argument " << x << endl; prod *= x; cout << "Current value of product is " << prod << endl; } ex result() const { return prod; } }; int main() { symbol a("a"), b("b"), c("c"); lst l; l = a, b, c; lst_prod test; for_each(l.begin(), l.end(), test); ex res = test.result(); cout << "---------------------"; cout << "List is " << l << endl; cout << "Product of it's elements is " << res << endl; return 0; } I expected res to be a*b*c, but the output is: We are called with argument a Current value of product is a We are called with argument b Current value of product is b*a We are called with argument c Current value of product is c*b*a --------------------- List is {a,b,c} Product of it's elements is 1 This looks like a bug or a very strange feature...

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small GiNaC query
by keith.briggs＠bt.com 27 Jan '04

27 Jan '04

How do I get the program below to compute 1/6*s.1^3+1/2*s.1*s.2+1/3*s.3 ? I don't care about ordering of summands, but I need the s.1*s.2 and s.2*s.1 terms to be merged and s.1*s.1*s.1 to be converted to s.1^3. Thanks, Keith // KMB 2004 Jan 26 // g++ -Wall tryginac1.cc -lginac && a.out #include <iostream> #include <stdexcept> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; ex Z(int n) { if (n==0) return 1; ex r=0; symbol s("s"),i_sym("i"); idx i(i_sym,n); for (int j=1; j<=n; j++) { ex si=indexed(s,i); r+=si.subs(i==j)*Z(n-j); } return r.expand().collect(s)/n; // -> 1/6*s.2*s.1+1/3*s.1*s.2+1/3*s.3+1/6*s.1*s.1*s.1 return simplify_indexed(r/n); // -> 1/6*s.2*s.1+1/3*s.1*s.2+1/3*s.3+1/6*s.1*s.1*s.1 return collect_common_factors(r/n); // -> 1/6*s.1*(s.2+s.1*s.1)+1/3*s.3+1/3*s.1*s.2 return r.expand()/n; // -> 1/6*s.1*s.1*s.1+1/6*s.1*s.2+1/3*s.3+1/3*s.1*s.2 } int main(void) { try { cout<<Z(3)<<endl; } catch (exception &p) { cerr << p.what() << endl; return 1; } return 0; } Dr. Keith M. Briggs Senior Mathematician, Complexity Research, BT Exact http://more.btexact.com/people/briggsk2/ (internet) http://research.btexact.com/teralab/keithbriggs.html (BT intranet) phone: +44(0)1473 work: 641 911 home: 610 517 fax: 642 161 mail: Keith Briggs, Polaris 134, Adastral Park, Martlesham, Suffolk IP5 3RE, UK

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Physical Units
by Lee Harding 23 Jan '04

23 Jan '04

I'm an engineer of the physical ilk (MSME), but semi-literate in the art of C++ programming. After discovering GiNaC today, I thought "nice library ". I've created a few programs for optimizing things, doing simple FEA (finite element analysis) and other sorts of calculations. Invariably, I end up restricting the domain to a consistent set of physical units (e.g. metric meter, kg, sec) or writing a lot of code to compensate for varying units across the input. For general-purpose tools, it can be a real pain in the shorts to get right. I haven't thought a great deal about why math libraries so consistently ignore the problem of unit consistency and conversion. But, I have failed to do it successfully with other libraries. For example, the Gnu project citrus[1] is a unit conversion library that implements it's own expression concept. Units and expressions are inextricably tied, I can't do my job without the old reliable kg/s/m^2 (aka. Newtons, aka. energy) after all. And, what is sin(pi)? Is that degrees or radians? It seems worthwhile to explore integrating physical units to GiNaC, if only to make like easier on poor engineers like myself. Is that a reasonable possibility? [1] http://citrus.sourceforge.net/

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Re: [Fwd: Re: Physical Units]
by Bernd Speiser 23 Jan '04

23 Jan '04

Kai Ludwig wrote: > > -------- Original Message -------- > Subject: Re: Physical Units > From: "Kai Ludwig" <kai.ludwig(a)uni-tuebingen.de> > Date: Fri, January 23, 2004 9:10 am > To: <ginac-list(a)zino.physik.uni-mainz.de> > > > I've created a few programs for optimizing things, doing simple FEA > > (finite element analysis) and other sorts of calculations. Invariably, > > I end up restricting the domain to a consistent set of physical units > > (e.g. metric meter, kg, sec) or writing a lot of code to compensate for > > varying units across the input. For general-purpose tools, it can be a > > real pain in the shorts to get right. Indeed, omitting units (and, for that matter, dimensions!) can lead to a lot of problems. By the way: in my opinion, sin(pi) is a number without dimension and unit (dimensionless number). However, it is interesting what unit the argument of the sin function, i.e. the pi, should have. Of course, this must be dimensionless. It could be a pure number, but it could equally well have a unit. It could result from some calculation with dimensioned quantities, which result in a dimensionless one. The Quantity library mentioned below does solve this problem by (a) checking the fact that the argument to a sin (and of course other such functions) to be dimensionless, (b) providing a type PureNumber, which can be used if a dimensionless quantity does not have any unit, and (c) if you want to work with an angle a type PlaneAngle (the name is according to IUPAC standards, the so-call Green Book), which can have units of Radian, Degree (not to be mixed up with temperature!!), Minute, Second, and Grade (all according to the Green Book). The Radian is the SI unit. Some general comment on Quantity follows below. > > Have a look at, > > http://sourceforge.net/projects/quantity > > this is a C++ template library designed for > unit conversions and unit type checking (already > at compile time). > As far as I know, there will be a new (redesigned) > release in due course. > The current version 0.6 of Quantity is still somehow preliminary. In particular, a lot of checking is still done at run time, resulting in considerable overhead. I am currently working on a thorough re-design where most of the functionality is shifted to compile time, and the type design is much more secure. I am not really finished, since I learned about static template metaprogramming (which is used for this re-design in many instances) only recently. This is not simple. I used some ideas of W. Brown (http://www.oonumerics.org/tmpw01/brown.pdf) and the possibilities of A. Alexandrescu's Typelist concept (A. Alexandrescu, Modern C++ Design. Generic Programming and Design Patterns Applied, Addison-Wesley, Boston, 2001). Unfortunately, the re-design also necessitates a slight re-design of the interface, so version 0.6 will not be fully compatible with the upcoming, more recent versions. If anyone is interested in the library, please let me know and/or check the announcements and news on the sourceforge page of the project. regards Bernd -- =================================================================== Bernd Speiser Institut f"ur Organische Chemie Auf der Morgenstelle 18 D-72076 T"ubingen Germany phone: +49-7071-2976205 (office) +49-7071-2976242 (laboratory) fax: +49-7071-295518 (new!) e-mail: bernd.speiser(a)uni-tuebingen.de Internet: http://www.uni-tuebingen.de/speiser ===================================================================

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