- non-integer powers are treated as 0 by (l)degree() and coeff()

[ginac.git] / ginac / power.cpp

diff --git a/ginac/power.cpp b/ginac/power.cpp
index 53342a9e57eef4bd751a614bda3f3d61b543524a..a0c6ea441620719d6b4dfb7d9f857b8a487999a3 100644 (file)
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -282,9 +282,12 @@ ex & power::let_op(int i)
 int power::degree(const symbol & s) const
 {
        if (is_exactly_of_type(*exponent.bp,numeric)) {
-               if ((*basis.bp).compare(s)==0)
-                       return ex_to_numeric(exponent).to_int();
-               else
+               if ((*basis.bp).compare(s)==0) {
+                       if (ex_to_numeric(exponent).is_integer())
+                               return ex_to_numeric(exponent).to_int();
+                       else
+                               return 0;
+               } else
                        return basis.degree(s) * ex_to_numeric(exponent).to_int();
        }
        return 0;
@@ -293,9 +296,12 @@ int power::degree(const symbol & s) const
 int power::ldegree(const symbol & s) const 
 {
        if (is_exactly_of_type(*exponent.bp,numeric)) {
-               if ((*basis.bp).compare(s)==0)
-                       return ex_to_numeric(exponent).to_int();
-               else
+               if ((*basis.bp).compare(s)==0) {
+                       if (ex_to_numeric(exponent).is_integer())
+                               return ex_to_numeric(exponent).to_int();
+                       else
+                               return 0;
+               } else
                        return basis.ldegree(s) * ex_to_numeric(exponent).to_int();
        }
        return 0;
@@ -305,17 +311,27 @@ ex power::coeff(const symbol & s, int n) const
 {
        if ((*basis.bp).compare(s)!=0) {
                // basis not equal to s
-               if (n==0) {
+               if (n == 0)
                        return *this;
-               } else {
+               else
                        return _ex0();
+       } else {
+               // basis equal to s
+               if (is_exactly_of_type(*exponent.bp, numeric) && ex_to_numeric(exponent).is_integer()) {
+                       // integer exponent
+                       int int_exp = ex_to_numeric(exponent).to_int();
+                       if (n == int_exp)
+                               return _ex1();
+                       else
+                               return _ex0();
+               } else {
+                       // non-integer exponents are treated as zero
+                       if (n == 0)
+                               return *this;
+                       else
+                               return _ex0();
                }
-       } else if (is_exactly_of_type(*exponent.bp,numeric)&&
-                          (static_cast<const numeric &>(*exponent.bp).compare(numeric(n))==0)) {
-               return _ex1();
        }
-
-       return _ex0();
 }
 
 ex power::eval(int level) const