abs() and conjugate() provide some info() now.

[ginac.git] / ginac / inifcns.cpp

diff --git a/ginac/inifcns.cpp b/ginac/inifcns.cpp
index cc0209208da959329d60fd3dbd9d1e1076d5d477..1144ce1997e14eed7911a6b6004a18fcc008b1a4 100644 (file)
--- a/ginac/inifcns.cpp
+++ b/ginac/inifcns.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's initially known functions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2011 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -76,8 +76,46 @@ static ex conjugate_imag_part(const ex & arg)
        return -arg.imag_part();
 }
 
+static bool func_arg_info(const ex & arg, unsigned inf)
+{
+       // for some functions we can return the info() of its argument
+       // (think of conjugate())
+       switch (inf) {
+               case info_flags::polynomial:
+               case info_flags::integer_polynomial:
+               case info_flags::cinteger_polynomial:
+               case info_flags::rational_polynomial:
+               case info_flags::real:
+               case info_flags::rational:
+               case info_flags::integer:
+               case info_flags::crational:
+               case info_flags::cinteger:
+               case info_flags::even:
+               case info_flags::odd:
+               case info_flags::prime:
+               case info_flags::crational_polynomial:
+               case info_flags::rational_function:
+               case info_flags::algebraic:
+               case info_flags::positive:
+               case info_flags::negative:
+               case info_flags::nonnegative:
+               case info_flags::posint:
+               case info_flags::negint:
+               case info_flags::nonnegint:
+               case info_flags::has_indices:
+                       return arg.info(inf);
+       }
+       return false;
+}
+
+static bool conjugate_info(const ex & arg, unsigned inf)
+{
+       return func_arg_info(arg, inf);
+}
+
 REGISTER_FUNCTION(conjugate_function, eval_func(conjugate_eval).
                                       evalf_func(conjugate_evalf).
+                                      info_func(conjugate_info).
                                       print_func<print_latex>(conjugate_print_latex).
                                       conjugate_func(conjugate_conjugate).
                                       real_part_func(conjugate_real_part).
@@ -197,6 +235,22 @@ static ex abs_eval(const ex & arg)
        if (is_ex_the_function(arg, abs))
                return arg;
 
+       if (is_ex_the_function(arg, exp))
+               return exp(arg.op(0).real_part());
+
+       if (is_exactly_a<power>(arg)) {
+               const ex& base = arg.op(0);
+               const ex& exponent = arg.op(1);
+               if (base.info(info_flags::positive) || exponent.info(info_flags::real))
+                       return pow(abs(base), exponent.real_part());
+       }
+
+       if (is_ex_the_function(arg, conjugate_function))
+               return abs(arg.op(0));
+
+       if (is_ex_the_function(arg, step))
+               return arg;
+
        return abs(arg).hold();
 }
 
@@ -212,7 +266,7 @@ static void abs_print_csrc_float(const ex & arg, const print_context & c)
 
 static ex abs_conjugate(const ex & arg)
 {
-       return abs(arg);
+       return abs(arg).hold();
 }
 
 static ex abs_real_part(const ex & arg)
@@ -227,14 +281,43 @@ static ex abs_imag_part(const ex& arg)
 
 static ex abs_power(const ex & arg, const ex & exp)
 {
-       if (arg.is_equal(arg.conjugate()) && is_a<numeric>(exp) && ex_to<numeric>(exp).is_even())
+       if (arg.is_equal(arg.conjugate()) && ((is_a<numeric>(exp) && ex_to<numeric>(exp).is_even())
+                                               || exp.info(info_flags::even)))
                return power(arg, exp);
        else
                return power(abs(arg), exp).hold();
 }
 
+bool abs_info(const ex & arg, unsigned inf)
+{
+       switch (inf) {
+               case info_flags::integer:
+               case info_flags::even:
+               case info_flags::odd:
+               case info_flags::prime:
+                       return arg.info(inf);
+               case info_flags::nonnegint:
+                       return arg.info(info_flags::integer);
+               case info_flags::nonnegative:
+               case info_flags::real:
+                       return true;
+               case info_flags::negative:
+                       return false;
+               case info_flags::positive:
+                       return arg.info(info_flags::positive) || arg.info(info_flags::negative);
+               case info_flags::has_indices: {
+                       if (arg.info(info_flags::has_indices))
+                               return true;
+                       else
+                               return false;
+               }
+       }
+       return false;
+}
+
 REGISTER_FUNCTION(abs, eval_func(abs_eval).
                        evalf_func(abs_evalf).
+                       info_func(abs_info).
                        print_func<print_latex>(abs_print_latex).
                        print_func<print_csrc_float>(abs_print_csrc_float).
                        print_func<print_csrc_double>(abs_print_csrc_float).
@@ -398,7 +481,7 @@ 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);
+                       return csgn(arg).hold();
                else
                        return power(csgn(arg), _ex2).hold();
        } else
@@ -489,7 +572,7 @@ static ex eta_series(const ex & x, const ex & y,
 
 static ex eta_conjugate(const ex & x, const ex & y)
 {
-       return -eta(x, y);
+       return -eta(x, y).hold();
 }
 
 static ex eta_real_part(const ex & x, const ex & y)
@@ -648,7 +731,7 @@ static ex Li2_conjugate(const ex & x)
        // conjugate(Li2(x))==Li2(conjugate(x)) unless on the branch cuts which
        // run along the positive real axis beginning at 1.
        if (x.info(info_flags::negative)) {
-               return Li2(x);
+               return Li2(x).hold();
        }
        if (is_exactly_a<numeric>(x) &&
            (!x.imag_part().is_zero() || x < *_num1_p)) {
@@ -687,7 +770,7 @@ static ex zetaderiv_eval(const ex & n, const ex & x)
        if (n.info(info_flags::numeric)) {
                // zetaderiv(0,x) -> zeta(x)
                if (n.is_zero())
-                       return zeta(x);
+                       return zeta(x).hold();
        }
        
        return zetaderiv(n, x).hold();