- GiNaC-list - ginac.de

CVS server moved
by Christian Bauer 15 Oct '05

15 Oct '05

Hi! As previously announced, the GiNaC CVS server has moved to the new location cvs.ginac.de. To do an anonymous checkout: $ cvs -d :pserver:anoncvs@cvs.ginac.de:/home/cvs/GiNaC login (password is 'anoncvs') $ cvs -d :pserver:anoncvs@cvs.ginac.de:/home/cvs/GiNaC co GiNaC If you are working with a copy checked out from the old CVS server, you need to do a fresh checkout from cvs.ginac.de. Happy hacking, Christian -- / Physics is an algorithm \/ www.cebix.net

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We are moving...
by Richard B. Kreckel 08 Oct '05

08 Oct '05

Dear all, Due to ongoing technical problems at Mainz University (*), it was decided to move GiNaC's and CLN's web server / CVS server / mailing lists to a rented server. This should allow us to continue communicating via mailing lists, doing development and updating the web pages, things that have become difficult during the last 10 weeks or so. We are going to move the DNS entries ASAP. The hosted machine's IP-address is going to be 81.169.130.167. We'll certainly see some outage while the transfer occurs, but hopefully not for long time. Meanwhile, you can all make sure the address you use as mailing list addresses is ...(a)ginac.de, not ...(a)thep.physik.uni-mainz.de or ...(a)zino.physik.uni-mainz.de because these will cease to work. We apologize for the inconveninece -richy. (*) Case in point: right now the web server is dead. -- Richard B. Kreckel <http://www.ginac.de/~kreckel/>

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Breaking News
by Richard B. Kreckel 07 Oct '05

07 Oct '05

Erlangen, October 6, 2005 (for immediate release) The GiNaC/CLN hackers, the leading providers of advanced mathematical software solutions for research and industrial applications, are proud to announce that their system scored second in the "Many Digits" Friendly Competition [0], held 3rd and 4th October at the Radboud University in Nijmegen, The Netherlands. Although Richard Kreckel, former vice president of GiNaC's PR department has retired into industry, he was available to compete against the world's finest exact real arithmetic hackers. "It was a thrilling experience" said Richard Kreckel at a meeting with press. "I basically started hacking on the competition problems Monday morning and stopped only an hour before our turn at the competition Tuesday afternoon. Little sleep compensated only by beer, coffee and lots of caffeinated peppermints. It was quite similar to those release parties at University." Maybe it wasn't enough caffeine, though. The winner at the competition was the MPFR team headed by Paul Zimmermann. Says Richard Kreckel: "Well, they certainly cut some corners. They discovered, coded and tested closed-form solutions for hard iterative problems, thus being better than anybody else by orders of magnitude. Their winning is well-deserved. Congratulations!" Other competing systems were iRRAM, Wolfram's Mathematica, Maple, RealLib, COMP, Few Digits and Bignum. Although only provisional rankings have been published so far [1], ground-shaking changes in the results are not expected. The "Many Digits" Friendly Competition was of purely numerical nature: none of the 24 competition problems called for symbolic manipulations. Hence, it really was a measure of CLN's numerical power, rather than GiNaC's symbolic flexibility. Bruno Haible, the original author of the CLN library could not be reached for a statement. It is assumed that he is busy hunting down bugs in several dozen GNU software packages at the same time. He has all the time. After all, he has retired to industry, too. [0] <http://www.cs.ru.nl/~milad/manydigits/> [1] <http://www.cs.ru.nl/~milad/manydigits/raw_provisional.html>

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Problem compiling CLN on Darwin.
by Chris Dams 06 Oct '05

06 Oct '05

Dear all, I tried to compile CLN on Darwin. To be precise, uname -a says Darwin macfarland.local 7.9.0 Darwin Kernel Version 7.9.0: Wed Mar 30 20:11:17 PST 2005; root:xnu/xnu-517.12.7.obj~1/RELEASE_PPC Power Macintosh powerpc When running make check, the following error is produced cd tests; make check ./exam dyld: /Users/dams/download/cln-1.1.9/tests/.libs/exam Undefined symbols: ___gxx_personality_v0 __ZNSt8ios_base4InitC1Ev __ZNSt8ios_base4InitD1Ev __ZSt9terminatev __ZSt4cerr __ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc __ZNSo3putEc Apparently the dynamic library loader cannot find some symbols of the standard C++ library. However, that is very strange, as having the linker printing diagnostics reveals that the static library /usr/lib/gcc/darwin/3.3/libstdc++.a is used. Does anyone know more about this platform, and how I can solve this problem? Best wishes, Chris

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normalization ambiguity
by Jonathan Brandmeyer 05 Oct '05

05 Oct '05

I recently discovered that expressions like pow(x - y, 2) can normalize to pow(y - x, 2) if y compares less than x (according to the ex_is_less comparator). Is this behavior deliberate? A particular test in the test suite (check/exam_normalization.cpp) normally only passes when pow(x - y, 2).normal() == pow(x-y, 2). Thanks, -Jonathan

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Yet another version of the patch
by Chris Dams 05 Oct '05

05 Oct '05

Hi again! I found yet another error. This time because combine_ex_with_coeff_to_pair should be used to insert something into an expairseq. The latest version of my patch is attached. Best wishes, Chris

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Syntact Ambiguity
by Alan Bromborsky 04 Oct '05

04 Oct '05

Consider the statements: lst test; test = x+2*y,A*z-B*pow(z,2),x+y+z; There is a problem here due to the "," in "pow(z,2)" which cases the list elements to be separated incorrectly. Do you need to change the list element separator?

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Geometric Algebra
by Alan Bromborsky 28 Sep '05

28 Sep '05

I am trying to use the clifford algebra classes to do geometric algebra. To do this I must do a grade decomposition of multivectors. Is there a way to use clifford to list to do this other than the case of a simple vector (not a multivector). In the call: lst clifford_to_lst(const ex & e, const ex & c, bool algebraic = true); what should "c" be to get a complete multivector expansion in terms of the basis blades of the algebra. Letting "c = clifford_unit()" only expands simple vectors. After doing a grade decompostion I need to calculate the inner and outer products of homogenous (pure) grade multivector.

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Maps and sets of symbols?
by John Pye 14 Sep '05

14 Sep '05

Hi again, I've got an application I'm working on which needs the ability to handle STL maps and sets containing symbols. In order to be able to use these classes, I have to define an ordering (a less-than operator) for symbols. At the moment I use the 'get_name' method and then compare symbol names as strings, but this isn't really ideal, since it takes a a lot of processing, plus GiNaC is quite happy to tolerate more than one symbol with the same name, so my map/set should be as well. I notice that GiNaC's symbol class has a 'serial number' as one of its properties. Is there any way I can access that value via a public method? Or is there another method suggested for creating sets and maps of symbols? //// Ordering for symbols based on name (there should be a better way)/ *class* symbol_lt{ *public*: bool *operator*()(const GiNaC::symbol &a, const GiNaC::symbol &b) const; }; Cheers JP

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Getting a pointer to an element in a list?
by John Pye 10 Sep '05

10 Sep '05

Hi all A hopefully pretty simple question about lists in GiNaC. I have a little fragment of code like this: class SymbolicSystem{ private: GiNaC::lst F; public: const ex * getExpressionPtr(const unsigned &i) const{ *return* &(F[i]); } } Is there something about the implementation of the operator[] in GiNaC::list that stops me from being able to do this? GCC gives me a warning, like this: warning: taking address of temporary This might be an elementary C++ mistake, but just in case, I thought I'd ask. Cheers JP

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