17489: deprecate superfluous functions

src/sage/rings/arith.py

@@ -334,6 +334,30 @@ def bernoulli(n, algorithm='default', num_threads=1):
         raise ValueError("invalid choice of algorithm")
 
 
+def factorial(n, algorithm='gmp'):
+    r"""
+    This version of ``factorial`` is deprecated. Please use
+    :meth:`sage.functions.other.factorial`.
+
+    EXAMPLES::
+
+        sage: from sage.rings.arith import factorial as fact
+        sage: fact(8)
+        doctest:...: DeprecationWarning: This version of factorial is deprecated. Please use sage.functions.other.factorial.
+        See http://trac.sagemath.org/17489 for details.
+        40320
+    """
+    from sage.misc.superseded import deprecation
+    deprecation(17489, 'This version of factorial is deprecated. Please use sage.functions.other.factorial.')
+    if n < 0:
+        raise ValueError("factorial -- must be nonnegative")
+    if algorithm == 'gmp':
+        return ZZ(n).factorial()
+    elif algorithm == 'pari':
+        return pari.factorial(n)
+    else:
+        raise ValueError('unknown algorithm')
+
 def is_prime(n):
     r"""
     Returns ``True`` if `n` is prime, and ``False`` otherwise.
@@ -3194,7 +3218,9 @@ def binomial(x, m, **kwds):
         P = type(x)
     if m < 0:
         return P(0)
-    return misc.prod([x-i for i in xrange(m)])/factorial(m)
+    else:
+        from sage.functions.other import factorial
+        return misc.prod([x-i for i in xrange(m)])/factorial(m)
 
 def multinomial(*ks):
     r"""
@@ -5266,6 +5292,7 @@ def subfactorial(n):
 
     - Jaap Spies (2007-01-23)
     """
+    from sage.functions.other import factorial
     return factorial(n)*sum(((-1)**k)/factorial(k) for k in range(n+1))
 
 

src/sage/symbolic/pynac.pyx

@@ -1294,19 +1294,11 @@ def py_tgamma_for_doctests(x):
 cdef public object py_factorial(object x) except +:
     """
     The factorial function exported to pynac.
-
-    TESTS::
-
-        sage: from sage.symbolic.pynac import py_factorial_py as py_factorial
-        sage: py_factorial(4)
-        24
-        sage: py_factorial(-2/3)
-        2.67893853470775
     """
     # factorial(x) is only defined for non-negative integers x
     # so we first test if x can be coerced into ZZ and is non-negative.
     # If this is not the case then we return the symbolic expression gamma(x+1)
-    # This fixes Trac 9240
+    # This fixes :trac:`9240`
     try:
         x_in_ZZ = ZZ(x)
         coercion_success = True
@@ -1320,16 +1312,18 @@ cdef public object py_factorial(object x) except +:
 
 def py_factorial_py(x):
     """
-    This function is a python wrapper around py_factorial(). This wrapper
-    is needed when we override the eval() method for GiNaC's factorial
-    function in sage.functions.other.Function_factorial.
+    Deprecated.
 
     TESTS::
 
         sage: from sage.symbolic.pynac import py_factorial_py
         sage: py_factorial_py(3)
+        doctest:...: DeprecationWarning: This version of factorial is deprecated. Please use sage.functions.other.factorial.
+        See http://trac.sagemath.org/17489 for details.
         6
     """
+    from sage.misc.superseded import deprecation
+    deprecation(17489, 'This version of factorial is deprecated. Please use sage.functions.other.factorial.')
     return py_factorial(x)
 
 cdef public object py_doublefactorial(object x) except +: