X-Git-Url: https://svn.cri.ensmp.fr/git/linpy.git/blobdiff_plain/5d2a146f1fa8ff16a9de6f35e74d59031fbcb575..4af78812d25b28cee283e671c0bd5944133b6ce5:/linpy/linexprs.py

diff --git a/linpy/linexprs.py b/linpy/linexprs.py
index 492ea9e..a49f90e 100644
--- a/linpy/linexprs.py
+++ b/linpy/linexprs.py
@@ -247,9 +247,10 @@ class LinExpr:
         """
         Test whether two linear expressions are equal.
         """
-        return isinstance(other, LinExpr) and \
-            self._coefficients == other._coefficients and \
-            self._constant == other._constant
+        if isinstance(other, LinExpr):
+            return self._coefficients == other._coefficients and \
+                self._constant == other._constant
+        return NotImplemented
 
     def __le__(self, other):
         from .polyhedra import Le
@@ -272,9 +273,9 @@ class LinExpr:
         Return the expression multiplied by its lowest common denominator to
         make all values integer.
         """
-        lcm = functools.reduce(lambda a, b: a*b // gcd(a, b),
+        lcd = functools.reduce(lambda a, b: a*b // gcd(a, b),
             [value.denominator for value in self.values()])
-        return self * lcm
+        return self * lcd
 
     def subs(self, symbol, expression=None):
         """
@@ -497,7 +498,9 @@ class Symbol(LinExpr):
         return True
 
     def __eq__(self, other):
-        return self.sortkey() == other.sortkey()
+        if isinstance(other, Symbol):
+            return self.sortkey() == other.sortkey()
+        return NotImplemented
 
     def asdummy(self):
         """