X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fpower.cpp;h=f5ab330d450f0c76ac2207ef0a047b7f1b6a39bb;hp=c6bf7b9770d2fa939eb242fef780f6aa84286dc5;hb=cca88b51436e4b654d16a4d60cd0d1c66fcf5dd6;hpb=5f896fa7f59bbce727e4bba23df9c4bbdbb55c29

diff --git a/ginac/power.cpp b/ginac/power.cpp
index c6bf7b97..f5ab330d 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's symbolic exponentiation (basis^exponent). */
 
 /*
- *  GiNaC Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2014 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
@@ -242,6 +242,8 @@ bool power::info(unsigned inf) const
 			return (flags & status_flags::expanded);
 		case info_flags::positive:
 			return basis.info(info_flags::positive) && exponent.info(info_flags::real);
+		case info_flags::nonnegative:
+			return basis.info(info_flags::real) && exponent.info(info_flags::integer) && exponent.info(info_flags::even);
 		case info_flags::has_indices: {
 			if (flags & status_flags::has_indices)
 				return true;
@@ -287,11 +289,16 @@ ex power::map(map_function & f) const
 
 bool power::is_polynomial(const ex & var) const
 {
-	if (exponent.has(var))
-		return false;
-	if (!exponent.info(info_flags::nonnegint))
-		return false;
-	return basis.is_polynomial(var);
+	if (basis.is_polynomial(var)) {
+		if (basis.has(var))
+			// basis is non-constant polynomial in var
+			return exponent.info(info_flags::nonnegint);
+		else
+			// basis is constant in var
+			return !exponent.has(var);
+	}
+	// basis is a non-polynomial function of var
+	return false;
 }
 
 int power::degree(const ex & s) const
@@ -362,7 +369,7 @@ ex power::coeff(const ex & s, int n) const
  *  - ^(1,x) -> 1
  *  - ^(c1,c2) -> *(c1^n,c1^(c2-n))  (so that 0<(c2-n)<1, try to evaluate roots, possibly in numerator and denominator of c1)
  *  - ^(^(x,c1),c2) -> ^(x,c1*c2)  if x is positive and c1 is real.
- *  - ^(^(x,c1),c2) -> ^(x,c1*c2)  (c2 integer or -1 < c1 <= 1, case c1=1 should not happen, see below!)
+ *  - ^(^(x,c1),c2) -> ^(x,c1*c2)  (c2 integer or -1 < c1 <= 1 or (c1=-1 and c2>0), case c1=1 should not happen, see below!)
  *  - ^(*(x,y,z),c) -> *(x^c,y^c,z^c)  (if c integer)
  *  - ^(*(x,c1),c2) -> ^(x,c2)*c1^c2  (c1>0)
  *  - ^(*(x,c1),c2) -> ^(-x,c2)*c1^c2  (c1<0)
@@ -480,7 +487,7 @@ ex power::eval(int level) const
 		}
 	
 		// ^(^(x,c1),c2) -> ^(x,c1*c2)
-		// (c1, c2 numeric(), c2 integer or -1 < c1 <= 1,
+		// (c1, c2 numeric(), c2 integer or -1 < c1 <= 1 or (c1=-1 and c2>0),
 		// case c1==1 should not happen, see below!)
 		if (is_exactly_a<power>(ebasis)) {
 			const power & sub_power = ex_to<power>(ebasis);
@@ -489,7 +496,8 @@ ex power::eval(int level) const
 			if (is_exactly_a<numeric>(sub_exponent)) {
 				const numeric & num_sub_exponent = ex_to<numeric>(sub_exponent);
 				GINAC_ASSERT(num_sub_exponent!=numeric(1));
-				if (num_exponent->is_integer() || (abs(num_sub_exponent) - (*_num1_p)).is_negative()) {
+				if (num_exponent->is_integer() || (abs(num_sub_exponent) - (*_num1_p)).is_negative() 
+						|| (num_sub_exponent == *_num_1_p && num_exponent->is_positive())) {
 					return power(sub_basis,num_sub_exponent.mul(*num_exponent));
 				}
 			}
@@ -735,8 +743,7 @@ ex power::imag_part() const
 	ex b=basis.imag_part();
 	ex c=exponent.real_part();
 	ex d=exponent.imag_part();
-	return
-		power(abs(basis),c)*exp(-d*atan2(b,a))*sin(c*atan2(b,a)+d*log(abs(basis)));
+	return power(abs(basis),c)*exp(-d*atan2(b,a))*sin(c*atan2(b,a)+d*log(abs(basis)));
 }
 
 // protected