July 2004 - GiNaC-devel

strange bug
by Ralf Stephan 11 Aug '04

11 Aug '04

Hello, the following program dumps core here. #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main() { symbol x("x"); ex e = (ex(1)/x).numer_denom(); e = e[0]; cerr << e; } But it outputs 1 as it should if I replace the last two lines with cerr << e[0]; I don't even understand the difference! Thanks for your time, ralf

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patch
by Chris Dams 02 Aug '04

02 Aug '04

Dear GiNaCers, The line if (return_type_tinfo() & 0xffffff00U != TINFO_clifford) { that occurs in ncmul::conjugate() needs to be changed into if ((return_type_tinfo() & 0xffffff00U) != TINFO_clifford) { for correct operator precedence. Best, Chris

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Re: content() inconsistencies
by Ralf Stephan 02 Aug '04

02 Aug '04

> > cout << (10*x/2+ex(15)/3).content(x) << endl; > > But that's 5x+5...? Oh well... yes. 15x/2+25/3 would be solved correctly by Pari. > Anyway, content() and primpart() in GiNaC currently only work correctly for > polynomials in Z[x]. But your Pari results are correct. The content of a > polynomial in Q[x] should be calculated in a way that the primitive part is > a polynomial in Z[x] with content 1. While going through the loop computing the gcd of the coeff numerators, one would simultaneously collect the lcm of the denominators, numeric or otherwise, with the end result gcd divided by lcm. I'm quite satisfied with the following patch. YMMV. The outcommented code was rather obscure to me. Thanks, ralf --- GiNaC-1.2.1-orig/ginac/normal.cpp Thu Jan 8 16:06:50 2004 +++ GiNaC-1.2.1/ginac/normal.cpp Fri Jul 2 16:51:17 2004 @@ -851,21 +851,25 @@ return _ex0; // First, try the integer content - ex c = e.integer_content(); - ex r = e / c; - ex lcoeff = r.lcoeff(x); - if (lcoeff.info(info_flags::integer)) - return c; +// ex c = e.integer_content(); +// ex r = e / c; +// ex lcoeff = r.lcoeff(x); +// if (lcoeff.info(info_flags::integer)) +// return c; // GCD of all coefficients int deg = e.degree(x); int ldeg = e.ldegree(x); if (deg == ldeg) return e.lcoeff(x) / e.unit(x); - c = _ex0; + ex c = _ex0, l = 1; for (int i=ldeg; i<=deg; i++) - c = gcd(e.coeff(x, i), c, NULL, NULL, false); - return c; + { + const ex& t = e.coeff(x,i).numer_denom(); + c = gcd(t[0], c, NULL, NULL, false); + l = lcm(t[1], l); + } + return c/l; }

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Majordomo is dead, long live Mailman!
by Christian Bauer 18 Jul '04

18 Jul '04

Hello! The GiNaC mailing lists are now running under the Mailman mailing list software. You should have received an Email with your personal subscription password and some instructions on how to change your subscription settings and how to unsubscribe. To fend off spam, only subscribed members can post to the lists now. If you are using multiple Email addresses for posting, you can subscribe all of them, and set all except one to "nomail" on the subscription options page, so you won't get duplicate messages. The list archives have been preserved and can be accessed here: http://thep.physik.uni-mainz.de/pipermail/ginac-list/ http://thep.physik.uni-mainz.de/pipermail/ginac-devel/ Have fun, Christian -- / Physics is an algorithm \/ http://www.uni-mainz.de/~bauec002/

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yet another patch.
by Chris Dams 02 Jul '04

02 Jul '04

Dear GiNaCers, Could you change the line return clifford(e, varidx(0, dim), rl); that occurs in the function dirac_slash into return clifford(e, varidx(0, dim), default_metric(), rl); for correct constructor invocation. Thanks! Best, Chris

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yet another patch.
by Chris Dams 02 Jul '04

02 Jul '04

Hello again, I think it is not good that conjugate(some expression) returns a function while (some expression).conjugate() returns an expression. This is inconsistent to what users are used to with, say, expand(e) and e.expand(). They will be surprised that conjugate(some expression).expand() does not expand anything. Bye, Chris

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patch for complex conj of additions.
by Chris Dams 02 Jul '04

02 Jul '04

Dear GiNaCers, I found out that complex conjugating a-a*gamma5 gives a--a*gamma5. This is because the minus in front of a*gamm5 is stored inside the add while the minus that comes from cc-ing a*gamma5 is stored in the multiplication. These are not cancelled. The solution is to have a separate add::conjugate function. A patch is attached. Best, Chris

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content() inconsistencies
by Ralf Stephan 02 Jul '04

02 Jul '04

Hello, this symbol x("x"), a("a"); cout << (a*x/2+a*a/3).content(x) << endl; cout << (x/2+ex(1)/3).content(x) << endl; cout << (10*x/2+ex(15)/3).content(x) << endl; gives a 1 5 while Pari says 1/6*a 1/6 5 but I'm of the opinion it should be 1/6*a 1/6 5/6 I would fix it in ginac but what's the official definition of content? Regards, ralf

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CLN 1.1.8 released
by Richard B. Kreckel 02 Jul '04

02 Jul '04

Hello! CLN version 1.1.8 is out and available from the usual FTP site [0]. It incorporates a fix for a long standing bug recently discovered by Niklas Knutsson and it finally has working support for the AMD64 platform, a.k.a. the Opteron. The reason for this broad advertisement is that whilst revamping the GiNaC mailing lists, Christian Bauer has been so kind to set up a list dedicated to CLN. It's powered by Mailman and you can find information on how to subscribe at [1]. Recently, it has become somewhat popular to use the GiNaC mailing lists for CLN related topics. While this has brought some liveliness to those lists we should try to use <cln-list(a)ginac.de> instead from now on. I do not intend to continue with selective announcements - from now on the list will be used instead and it is recommended that you subscribe if your interest is fervent. :-) Regards -richy. [0] <ftp://ftpthep.physik.uni-mainz.de/pub/gnu/> [1] <http://thep.physik.uni-mainz.de/mailman/listinfo/cln-list> -- Richard B. Kreckel <http://www.ginac.de/~kreckel/>

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