Changeset 4258:a1131bb15e78 for sage/calculus/calculus.py

Timestamp:

04/29/07 23:05:27 (6 years ago)

Author:

William Stein <wstein@…>

Branch:

default

Message:

mostly work on sqrt for power series.

File:

• sage/calculus/calculus.py (modified) (1 diff)

sage/calculus/calculus.py

@@ -363 +363 @@
 
     def __nonzero__(self):
-        # Best to error on side of being nonzero in most cases. 
-        return not bool(self == SR.zero_element())
+        try:
+            return self.__nonzero
+        except AttributeError:
+            # Best to error on side of being nonzero in most cases. 
+            ans = not bool(self == SR.zero_element())
+            self.__nonzero = ans
+        return ans
 
     def __str__(self):