Dear all, Here is the full patch for the power property of csgn() function. Its effect can be seen in the following ginsh output:
csgn(x)^3; csgn(x) csgn(x)^5; csgn(x) csgn(x)^2; csgn(x)^2 csgn(x)^(2/5); csgn(x)^(2/5) csgn(x)^(6/2); csgn(x) csgn(x)^(-2); csgn(x)^(-2) csgn(x)^(-3); csgn(x)^(-3) csgn(x)^(-3/3); csgn(x)^(-1) csgn(x)^(-3/2); csgn(x)^(-3/2)
Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv@maths.leeds.ac.uk -- www: http://maths.leeds.ac.uk/~kisilv/ Index: ginac/inifcns.cpp =================================================================== RCS file: /home/cvs/GiNaC/ginac/inifcns.cpp,v retrieving revision 1.87 diff -u -r1.87 inifcns.cpp --- ginac/inifcns.cpp 13 Mar 2006 14:21:47 -0000 1.87 +++ ginac/inifcns.cpp 13 Mar 2006 15:56:20 -0000 @@ -252,10 +252,23 @@ return csgn(arg); } +static ex csgn_power(const ex & arg, const ex & exp) +{ + if (is_a<numeric>(exp) && exp.info(info_flags::positive) && ex_to<numeric>(exp).is_integer()) { + if (ex_to<numeric>(exp).is_odd()) + return csgn(arg); + else + return power(csgn(arg), _ex2).hold(); + } else + return power(csgn(arg), exp).hold(); +} + + REGISTER_FUNCTION(csgn, eval_func(csgn_eval). evalf_func(csgn_evalf). series_func(csgn_series). - conjugate_func(csgn_conjugate)); + conjugate_func(csgn_conjugate). + power_func(csgn_power)); //////////