Ticket #7828: trac_7828-reviewer.patch

sage/functions/generalized.py

@@ -52 +52 @@
 ##############################################################################
 
 from sage.symbolic.function import BuiltinFunction
-from sage.rings.complex_interval_field import ComplexIntervalField
+from sage.rings.all import ComplexIntervalField, ZZ
 
 class FunctionDiracDelta(BuiltinFunction):
     r"""
@@ -473 +473 @@
         """
         if hasattr(x,'sign'): # First check if x has a sign method
             return x.sign()
+        if hasattr(x,'sgn'): # or a sgn method
+            return x.sgn()
         try:
             approx_x = ComplexIntervalField()(x)
             if bool(approx_x.imag() == 0):      # x is real
                 if bool(approx_x.real() == 0):  # x is zero
-                    return 0
+                    return ZZ(0)
                 # Now we have a non-zero real
                 if bool((approx_x**(0.5)).imag() == 0): # Check: x > 0
-                    return 1
+                    return ZZ(1)
                 else:
-                    return -1
+                    return ZZ(-1)
         except:                     # x is symbolic
             pass    
         return None