Put back the general wrapping "error to NaN" so that it handles a fun…

…ction with whatever number of arguments. test_uncertainties passes.

uncertainties/__init__.py

@@ -1480,9 +1480,9 @@ def nan_if_exception(f):
         of the exceptions from the exceptions tuple.
         '''
 
-        def wrapped_f(x, y):
+        def wrapped_f(*args):
             try:
-                return f(x, y)
+                return f(*args)
             except exceptions:
                 return float('NaN')
 

uncertainties/test_umath.py

@@ -287,4 +287,14 @@ def test_math_module():
             assert err_math.args == err_ufloat.args
         else:
             raise Exception('ValueError exception expected')
+
 
+def test_hypot():
+    '''
+    Special cases where derivatives cannot be calculated:
+    '''
+    x = uncertainties.ufloat(0, 1)
+    y = uncertainties.ufloat(0, 2)
+    # Derivatives that cannot be calculated simply return NaN, with no
+    # exception being raised, normally:
+    umath.hypot(x, y)

uncertainties/test_uncertainties.py

@@ -1258,6 +1258,7 @@ def test_covariances():
     # Non-diagonal elements:
     assert _numbers_close(covs[0][1], -0.02)
 
+
 ###############################################################################
 def isnan(x):
     '''

uncertainties/umath.py

@@ -198,6 +198,12 @@ def log_der0(*args):
     else:
         continue  # 'name' not wrapped by this module (__doc__, e, etc.)
 
+    # Errors during the calculation of the derivatives are converted
+    # to a NaN result: it is assumed that a mathematical calculation
+    # that cannot be calculated indicates a non-defined derivative
+    # (the derivatives in fixed_derivatives must be written this way):
+
+
     func = getattr(math, name)
 
     setattr(this_module, name,