- GiNaC-devel - ginac.de

Library bug
by Pol Dell'aiera 17 Dec '00

17 Dec '00

hi ginac team ! Your program seems to be marvellous but... I download and compile the CLN library and this is what my computer said when i try to compile it...: **** The following problems have been detected by configure. **** Please check the messages below before running "make". **** (see the section 'Common Problems' in the INSTALL file) ** No suitable installed version of CLN could be found. deleting cache ./config.cache pol@linux:~/2compile/GiNaC-0.7.0 > Here you are. Uname -a :Linux linux 2.2.16 #1 Wed Aug 2 20:22:26 GMT 2000 i586 unknown gcc version: 2.95.2 Please, help us ! -pol- url: http://blenderman.free.fr/ icq: 38236098

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Release 0.7.0 is on the wire
by Richard B. Kreckel 15 Dec '00

15 Dec '00

Hi all, I have just finished packaging GiNaC 0.7.0. It is sitting at the usual places, see <http://www.ginac.de/Download.html>. Beware that you really do need CLN 1.1 (silently released yesterday) in order to use it! This is so, because CLN 1.1 is interface-incompatible (namespace cln) with earlier versions of CLN and GiNaC 0.7.0 is expecting the new interface. For those of you (Eduardo, Bernard) who want to extract a cln::cl_N from GiNaC::numeric for various reasons, there is now a method GiNaC::numeric::to_cl_N() which does right that. (I was first having a casting operator in mind, but that turned out to lead into ambiguities quite easily so we'll use .to_cl_N() from now on.) Cint users should upgrade to at least 5.14.62 in order to use GiNaC-cint with the current release. So, this is the list of required package versions and the order of steps how to proceed: * Install GMP >= 3.0 (current is 3.1.1) (optional) * Install CLN >= 1.1 (current is 1.1) * Install Cint >= 5.14.62 (current is 5.14.65) (optional) * Install GiNaC 0.7.0 * rejoice, cheer, sing... ;-) We plan to provide .deb and .rpm packages next week. And please read the file NEWS to see what else has changed. Happy hacking -rbk. -- Richard Kreckel <Richard.Kreckel(a)Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>

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Re: Autoconf
by Richard B. Kreckel 17 Nov '00

17 Nov '00

Hi Bernard, I just put this on the devel-list, maybe Christian or Alex have comments on the topic (or someone else): >>>>> On Fri, 27 Oct 2000, Parisse Bernard wrote: >>>>>[ ...talking about converting the expairseq-representation of add and mul >>>>>to a sparse tensor representation by pulling out all of the numbers... ] >>>>> I don't think there are efficiency problems there, maybe we loose a >>>>> small constant factor but that's not where time is critical. >>>>> What do you think of the idea of adding member functions to provide >>>>> read-only access to .rest and .coeff? That would keep my code more >>>>> readable and keep member protection. >>>>> >>>> On Fri, 27 Oct 2000, Richard Kreckel wrote: >>>> Grudgingly so. We might wish to change the internal representation of add >>>> and mul, although this doesn't seem very likely at the moment. The .op() >>>> access method is the preferred one. I think that it can be done more >>>> elegantly than what I did (and also more correctly). >>>> >>> On Sat, 28 Oct 2000, Parisse Bernard wrote: >>> I'm afraid that using e.g. >>> is_exactly_of_type(obj.op(obj.nops()),numeric) >>> instead of obj.overall_coeff would be as well broken if you change the >>> internal representation of add. >>> I don't think that internal representation can be fully hidden >>> when converting representations to another one. That's not a big >>> issue as long as you keep all the dependant code well isolated >>> and documented. And I believe that the most important thing for the >>> future is code maintenance ease where readability is a key feature. >>> >> On Sat, 28 Oct 2000, Richard Kreckel wrote: >> Not really. We want to have it this way: The last one (obj.nops()-1 that >> is) is *supposed* to be the numeric overall coefficient, if it is >> different from the default coefficient, 0 for add, 1 for mul. It is just >> as in Maple, but we don't have a head part, so the counting is different. >> But the last one returned is always the numeric part. That's a kind of >> contract and we are in some other pieces of code really relying on it. I >> guess I should add checking this in the exam part... >> > On Sun, 29 Oct 2000, Parisse Bernard wrote: > OK, but I'm not a Maple expert. In fact, I want to use C++ because > there are some aspects of CAS langages that I do not like at all (and > of course I don't want to use proprietary software anymore) like > those you mention in your article (e.g. using list of lists to represent > complex data structures). > As I said before I find more natural to learn the internal structure > of symbolic objects than to learn conventions that are not intrinsic. > At first, it seems a better idea to have such sort of conventions and > allow internal representation changes, but I don't believe you can > keep this working. Algorithms, at least if you need efficient ones > (and that's always the case for CAS algorithms), depends too much of > the data structure. I've read in Stroustrup's book a lot of > recommendations about good programming that have always exceptions when > you deal with maths. This would still leave us with the question how to access expairseq::seq.coeff and expairseq::overall_coeff from outside. Is the foo.op(foo.nops()-1) approach something one should live with or should we accept that others expect the representation as it is and add inspector methods? I would really appreciate some input on this. [ ...talking about the merits of add and mul's representation... ] > I did not know about such a representation before reading GiNaC doc > and source. I have experience with the HP calculator system that > represent symbolic objects as programs to be evaluated using a > stack (for exemple '1+x' as SYMBOL 1 identifier_X + ;). > This kind of representation is fairly easy to evaluate but more > difficult to split into subtrees because embedded algebraics were not > allowed. And it does accept the + as a binary operator only. Which > makes rather difficult to code some operations, like a+d+b+c -> a+b+c+d. > Moreover there are a lot of operations allowed inside symbolics: /, INV, > SQRT, SQ, ... so that early simplifications like 1/INV(x) -> x are > much harder to code than using your representation. > Hence I adopted your representation because it solves some of these > issues. I don't think you will find the need to change internal > representation of these fundemental objects. > The main problem I see currently is that you can not bind objects > to a symbol (I would like to do that and I would like to be able > to make assumptions on symbols as well). And I have to get a better > understanding of your coding of operations like SIN, ... > There is another problem I see with using CLN to compute e.g. > transcendental functions if special values are found, e.g. ATAN(1), > because symbolic values belong to GiNaC, not to CLN (or maybe I've > missed something). Ah, yes. We cannot really do much here. Automatically, all that is allowed is a simple evaluation if one thinks the resulting expression is "simpler". (In the case of atan(1) not doing so is clearly a bug and I'll fix it right now.) Following common jargon (eg R.J. Fateman in his article "Symbolic Mathematics System Evaluators" in Michael Westers "CAS - A practical guide") we can call this process of what is done automatically the "evaluator". We thought a useful convention is that automatically only fast transformations are done: on container-objects consisting of n things, this includes everything that goes like n*log(n) in complexity. Of course CLN does not have such a thing like Pi/4 because Pi doesn't fit into one of the algebraic domains there. So GiNaC simply tries to trap those arguments and give you a closed result in terms of well-known constants, including non-nested surds. Regards -richy. -- Richard Kreckel <Richard.Kreckel(a)Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>

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strange behavior of ex constructor from string
by Parisse Bernard 24 Oct '00

24 Oct '00

I'm currently testing the latest version of the Z-factorization code and found some weierd results that I believe show there is a bug in the ex constructor from a string. You can reproduce this bug the following way: compile the latest ftp://fourier.ujf-grenoble.fr/pub/hp48/giac.tgz (make install then make factor) Try ./factor zimmer7 answer is 0 Looking in my code, it seems that the call args.push_back(ex(string(ss2),lst(sym))); line 480 of polygauss.cc pushes a 0 instead of the correct expression (i.e. what's in the zimmer7 file) (you can check this by putting a breakpoint in factor.cc, l.27, p it->dbgprint() prints 0) The same call works when applied to zimmer1, zimmer2, zimmer3. Any ideas? Bye, Bernard

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factorization with GiNaC (update)
by Parisse Bernard 27 Sep '00

27 Sep '00

Hello, I have updated the polynomial package over GiNaC, especially factorization: ftp://fourier.ujf-grenoble.fr/pub/hp48/giac.tgz Main changes: * 2 version are available: you can either use giac with the NTL univariate factorization library or standalone * the code is faster. Installation requires gmp, cln and GiNaC, optionnaly NTL. Some timimgs of the standalone version on a Celeron 533 Mhz (# Time 0 means <=0.01 sec) (c+x+b)*(b^2-c*x+x^2-c*b+c^2-x*b) # Time0 (x+y+z)*(x-y+z)*(x-y-z) # Time0.01 (-5+3*x+y-y^2)*(-1+3*x+x*y-y^2) # Time0.01 (x-3*y+y*z)*(2*x-z+x*y)*(1+x*z+x*y+6*x^3) # Time0.02 (x*y+y^2+x^2)*(-x*y+y^2+x^2)*(x-y)*(-x-y) # Time0.01 (2+x^3+13*x*y*z^2-21*x*y^3*z)*(1+x*z+x*y+6*x^3) # Time0.01 2+x^3+13*x*y*z^2-21*x*y^3*z # Time0.01 x^2*y^2*(-x+y)*z^5*(-x-y-z) # Time0.01 -x^3*y^2*z*(x-y-z)*(-x+y-z)*(-x-y-z) # Time0.01 (8+15*x)*(1+8*x)*(11+5*x)*(-31+30*x)*(-13+12*x)*(-209+120*x) # Time0.01 (1+x^5+x^20+x^10+x^15)*(1-x^5+x^20+x^10-x^15) # Time0.02 (1+x^35+x^5-x^20+x^40-x^25-x^15)*(1-x^35-x^5-x^20+x^40+x^25+x^15)*(1+x-x^4+x^8-x^5-x^3+x^7)*(1-x-x^4+x^8+x^5+x^3-x^7)*(1+x+x^2)*(1-x+x^2) # Time0.13 If you are factoring big polynomials, the NTL version should be used instead of the standalone version (since it does not include e.g. FFT polynomial multiplication ...) Bernard Parisse

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the expand() thing.
by Richard B. Kreckel 22 Sep '00

22 Sep '00

Hi there, Recently I have been talking with Alex about a weird inefficency of GiNaC's expand() that showed up in some series expansion. It reappeared, this time in a clearer form, when I tried to implement an asymptotically optimal algorithm for computing characteristic polynomials (by transforming the matrix to an upper block-Frobenius form, but that's uninteresting here). That algorithm gives the characteristic polynomial in a partly factorized form and when I expand it I see horrible execution times or even worse, memory exhaustions. Consider this: > expand((-1+5*x-5*x^4-10*x^2+x^5+10*x^3)*(1-4*x+x^4+6*x^2-4*x^3)* (-1+7*x-35*x^4-21*x^2+21*x^5-7*x^6+35*x^3+x^7)* (1-8*x+70*x^4+28*x^2+x^8-56*x^5+28*x^6-56*x^3-8*x^7)* (1-6*x+15*x^4+15*x^2-6*x^5+x^6-20*x^3)*(-1+x)^36* (-1+9*x+x^9-126*x^4-36*x^2-9*x^8+126*x^5-84*x^6+84*x^3+36*x^7)^2* (1-2*x+x^2)); Out of virtual memory. > expand((-1+5*x-5*x^4-10*x^2+x^5+10*x^3)*(1-4*x+x^4+6*x^2-4*x^3)* (-1+7*x-35*x^4-21*x^2+21*x^5-7*x^6+35*x^3+x^7)* (1-8*x+70*x^4+28*x^2+x^8-56*x^5+28*x^6-56*x^3-8*x^7)* (1-6*x+15*x^4+15*x^2-6*x^5+x^6-20*x^3)*(-1+x)^36* (-1+9*x+x^9-126*x^4-36*x^2-9*x^8+126*x^5-84*x^6+84*x^3+36*x^7)^2* (1-2*x+x^2)*(-75810815066186520+75810815066186521*x+165*x^9-165*x^4-11*x^2-330* x^8+11*x^11+330*x^5-55*x^10-462*x^6+55*x^3-x^12+462*x^7)*(-1+3*x-3*x^2+x^3)); bad_alloc Virtual memory was 1GB. (BTW: The second polynomial is identical to the one computed in expanded form in check/time_lw_P.cpp.) Alex, would you be able to have a look into this? Cheers -richy. -- Richard Kreckel <Richard.Kreckel(a)Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>

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download
by Ricardo Guzman 07 Sep '00

07 Sep '00

I'm having problems extracting the source code from the tar file: GiNaC-0.6.4.tar.bz2. I believe it may be corrupt. Could you verify this? Thanks Ricardo Guzman

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factorization with GiNaC
by Parisse Bernard 23 Aug '00

23 Aug '00

Hello, I have uploaded at ftp://fourier.ujf-grenoble.fr/pub/hp48/giac.tgz the latest version of my polynomial library with a beta version of a factorization algorithm. See README for installation, and try sh test.factor to test the factorization. Now waiting for bug reports:-) Bernard

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Cint 5.14.45
by Richard B. Kreckel 12 Aug '00

12 Aug '00

I just found an error in GiNaC's INSTALL file. The last line should read > 5.14.45 | compiles fine, works like a charm instead of < 5.14.45 | compiles fine, still some weirdnesses during execution I had a wrong link when I tried it. :-) -richy. -- Richard B. Kreckel <Richard.Kreckel(a)Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>

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GiNaC 0.6.4 is on the wire.
by Richard B. Kreckel 10 Aug '00

10 Aug '00

Hello, folx! I justed tagged GiNaC 0.6.4 and uploaded it to the usual places. No new functionality was introduced. During the last weeks we ran the complete check-suite thousands of times and were somewhat surprised to find a couple of nasty bugs. Those have been killed and now the check-suite doesn't seem to find any more. Until somebody decides to re-introduce them... Here is the entry from the NEWS file: * Complete revamp of methods in class matrix. Some redundant (and poor) implementations of elimination schemes were thrown out. The code is now highly orthogonal, more flexible and much more efficient. * Some long standing and quite nasty bugs were discovered and fixed in the following functions: add::normal(), heur_gcd(), sr_gcd() and Order_eval() (thanks to Bernard Parisse). Enjoy -richy. -- Richard B. Kreckel <kreckel(a)ginac.de> <http://www.ginac.de/~kreckel/>

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