- GiNaC-devel - ginac.de

polynomial arithmetic over ginac
by Parisse Bernard 23 May '01

23 May '01

I have now a little bit improved the package of my polynomial and rational fractions utilities over GiNaC (0.6.4) It provides now gcd normalization, factor (square-free and rational roots), partfrac & integrate (assuming factor works on the denominator), for example: integrate '1/(x^4-1)^5' returns -1155/8192*log(1+x)-1155/4096*atan(x)+1155/8192*log(-1+x)+1/2048*(-893*x-1375*x^9+1755*x^5+385*x^13)*(-1+x^4)^(-4) # Time for (integrate)0.04 You can retrieve and test it at ftp://fourier.ujf-grenoble.fr/pub/hp48/giac.tgz Bye, Bernard Parisse

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Wildcards for subs()
by Christian Bauer 23 May '01

23 May '01

Hi! It has been suggested to me that it would be a desirable feature for subs() to be able to specify wildcards for indices and function arguments so you could, for example - in "sin(x-1)+sin(2*y)", substitute sin(?) by cos(?)/2 to get "cos(x-1)/2+cos(2*y)/2" - in "atan2(x+y,z^2)", substitute atan2(?1,?2) by ?2/?1 to get "z^2/(x+y)" - in "F.mu*g.nu.rho+F.nu*g.mu.rho", substitute F.? by a.?+b.? to get "(a.mu+b.mu)*g.nu.rho+(a.nu+b.nu)*g.mu.rho" This should be relatively easy to implement by extending indexed::subs() and function::subs() and adding a new "wildcard/wild" class that has an integer member to distinguish multiple wildcards. Function substitution would then go something like e.subs(atan2(wild(1), wild(2)) == wild(2)/wild(1)); and substitution of base expressions of indexed objects is similar: e.subs(indexed(wild(), mu) == indexed(wild(), mu)/2+indexed(A, mu)); Wildcards for indices are a little more involved because indices must be of class idx, so one would have to write e.subs(indexed(F, varidx(wild(), 4)) == indexed(a, varidx(wild(), 4)) + indexed(b, varidx(wild(), 4))); which is a little clumsy but has the advantage of taking index dimensions and variance into account (this can also be a disadvantage because it could only substitute F~mu, not F.mu). Any comments/suggestions? Bye, Christian -- / Coding on PowerPC and proud of it \/ http://www.uni-mainz.de/~bauec002/

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bug: get_precedence() is not working
by Pearu Peterson 20 May '01

20 May '01

Hi again, The output of, for example #include <ginac/ginac.h> using namespace GiNaC; main() { symbol x("x"), y("y"); std::cout << ex_to_add(x+y).get_precedence() << std::endl; } should be 40 but I am getting 70 It seems to me that one has to define for each class, that redefines basic::precedence, also the get_precedence() function. Clearly it is not C++ way, but may be it is due to that basic::precedence is defined static. Sorry, but right now I don't have any idea how to fix it... Pearu

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mul::print bug
by Pearu Peterson 16 May '01

16 May '01

Hi! It appears that in the print_csrc context of mul::print function a line if (precedence <= level) is missing just before of the line #139 in mul.cpp c.s << "("; which is causing the following incorrect result: >>> ((x+y)**(x*y)).to_csrc() pow(y+x,(y*x) for instance. Regards, Pearu

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Version 0.8.3 is on the wire.
by Richard B. Kreckel 11 May '01

11 May '01

This is from the NEWS file: - color and clifford classes are functional and documented. - New "spinidx" class for dotted/undotted indices. - Predefined spinor metric tensor (created by spinor_metric()). - Symbols can have a LaTeX name, e.g. symbol s("s", "\\sigma"); - LaTeX output of indexed objects is much nicer. - Fix some build-problems (with recent libreadline). (*) - Semantics of arithmetic operators now follows the C++ rules more strictly. (*) Hi Julian! ;-) Enjoy -richy. -- Richard Kreckel <Richard.Kreckel(a)Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>

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Wishlist (relational, pseries, matrix)
by Pearu Peterson 07 May '01

07 May '01

Hi! I have been working with GiNaC's interface to Python for some time now and I have collected the following notes that I have found important in this kind of applications: 1) Having relational::get_operator() would be useful (read: necessary) for extensions that can perform symbolic operations like (a < b) && (b > a) -> a < b 2) If a,b are compatible pseries then ex(a) * ex(b) would automatically produce ex(a.mul_series(b)) The same for operations +,-,scalar_mul,scalar_div. If a,b are incompatible, then apply current behaviour (that is, do nothing). I have implemented this behaviour in the GiNaC->Python interface but it does not cover cases where multiplication is carried out inside GiNaC functions. I am thinking of applications where, for example, a matrix consists of compatible pseries and the task is to find its inverse. 3) If a,b are compatible matrices (for a given operation) then ex(a) * ex(b) -> ex(a.mul(b)) The same for operations +,-,scalar_mul,scalar_div. That's all for now. Regards, Pearu

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gTybalt 0.0.4
by Stefan Weinzierl 03 May '01

03 May '01

Dear all, for those who are interested, I put a new version of gTybalt on the web. (http://www.fis.unipr.it/~stefanw/gtybalt.html) gTybalt is a small program build on top of some other packages (GiNaC, TeXmacs, Root, ...) and provides basically TeX-type fonts output for GiNaC and some basic plotting routines. The installation of the new version has become a little bit more user-friendlier, no modifications or adjustment of TeXmacs or GiNaC are needed any more. Enjoy it, Stefan

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version 0.8.2 again ginsh compile broken with libreadline4 in Debian?
by Julian Stoev 25 Apr '01

25 Apr '01

Here are the compiler messages: make[2]: Entering directory `/var/tmp/GiNaC-0.8.2/ginsh' sed -n -f ./ginsh_fcn_help.sed <ginsh.1 >ginsh_fcn_help.c sed -n -f ./ginsh_op_help.sed <ginsh.1 >ginsh_op_help.c c++ -DHAVE_CONFIG_H -I. -I. -I.. -I./../ginac -I../ginac -DIN_GINAC -g -O2 -c ginsh_parser.cc In file included from /usr/include/readline/keymaps.h:37, from /usr/include/readline/readline.h:37, from ginsh.h:36, from ginsh_parser.yy:41: /usr/include/readline/rltypedefs.h:48: invalid exception specifications /usr/include/readline/rltypedefs.h:51: invalid exception specifications /usr/include/readline/rltypedefs.h:52: invalid exception specifications /usr/include/readline/rltypedefs.h:54: invalid exception specifications /usr/include/readline/rltypedefs.h:55: invalid exception specifications /usr/include/readline/rltypedefs.h:57: invalid exception specifications /usr/include/readline/rltypedefs.h:59: invalid exception specifications /usr/include/readline/rltypedefs.h:62: invalid exception specifications /usr/include/readline/rltypedefs.h:65: invalid exception specifications /usr/include/readline/rltypedefs.h:70: invalid exception specifications /usr/include/readline/rltypedefs.h:73: invalid exception specifications /usr/include/readline/rltypedefs.h:75: invalid exception specifications /usr/include/readline/rltypedefs.h:76: invalid exception specifications /usr/include/readline/rltypedefs.h:78: invalid exception specifications /usr/include/readline/rltypedefs.h:79: invalid exception specifications /usr/include/readline/rltypedefs.h:80: invalid exception specifications /usr/include/readline/rltypedefs.h:81: invalid exception specifications In file included from /usr/include/readline/readline.h:38, from ginsh.h:36, from ginsh_parser.yy:41: /usr/include/readline/tilde.h:55: invalid exception specifications ginsh_parser.yy: In function `char ** fcn_completion(char *, int, int)': ginsh_parser.yy:705: `filename_completion_function' undeclared (first use this function) ginsh_parser.yy:705: (Each undeclared identifier is reported only once ginsh_parser.yy:705: for each function it appears in.) ginsh_parser.yy:705: implicit declaration of function `int completion_matches(...)' ginsh_parser.yy:711: return to `char **' from `int' lacks a cast ginsh_parser.yy: In function `int main(int, char **)': ginsh_parser.yy:777: assignment to `char *' from `const char *' discards qualifiers make[2]: *** [ginsh_parser.o] Error 1 make[2]: Leaving directory `/var/tmp/GiNaC-0.8.2/ginsh' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/var/tmp/GiNaC-0.8.2' make: *** [all-recursive-am] Error 2 When I compile ginac without ginsh, it compiles fine. --JS

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ginsh broken with libreadline4 in Debian?
by Julian Stoev 24 Apr '01

24 Apr '01

I can not compile ginsh on Debian unstable. I can not cut/paste the compile messages right now, but it would be interesting if somebody compiled it on Debian unstable (libreadline4). --JS

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Version 0.8.2...
by Richard B. Kreckel 24 Apr '01

24 Apr '01

...claims to feature the following new stuff: * degree(), ldegree(), coeff(), lcoeff(), tcoeff() and collect() work with non-symbols as the second argument in ginsh. * the argument to collect() can be a list of objects in which case the result is either a recursively collected polynomial, or a polynomial in a distributed form with terms like coeff*x1^e1*...*xn^en, as specified by the second argument to collect(). * Several bugfixes (including a nasty memory leak in .normal()). * class matrix: solve() doesn't call algorithms redundantly any more and inverse() falls back to solve() which works in more general cases. Enjoy -richy. -- Richard Kreckel <Richard.Kreckel(a)Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>

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