details: http://hg.sympy.org/sympy/rev/6422f5d608d2
changeset: 1839:6422f5d608d2
user: Andy R. Terrel <[EMAIL PROTECTED]>
date: Sun Oct 19 21:41:36 2008 +0200
description:
Adding sympify call to canonized arguments and refactoring code.
diffs (140 lines):
diff -r 2bd730295d9f -r 6422f5d608d2 sympy/functions/elementary/piecewise.py
--- a/sympy/functions/elementary/piecewise.py Sun Oct 19 20:26:03 2008 +0200
+++ b/sympy/functions/elementary/piecewise.py Sun Oct 19 21:41:36 2008 +0200
@@ -40,6 +40,10 @@
if opt in options:
del options[opt]
r = cls.canonize(*args)
+
+ # sympify args
+ args = map(lambda x:(sympify(x[0]), sympify(x[1])), args)
+
if r is None:
return Basic.__new__(cls, *args, **options)
else:
@@ -49,14 +53,15 @@
def canonize(cls, *args):
# Check types first
for ec in args:
- if (not isinstance(ec,tuple)) or len(ec)!=2:
+ if (not isinstance(ec, tuple)) or len(ec)!=2:
raise TypeError, "args may only include (expr, cond) pairs"
for expr, cond in args:
cond_type = type(ec[1])
- if cond_type != bool and not issubclass(cond_type,Relational):
+ if cond_type != bool and not issubclass(cond_type, Relational) and\
+ not issubclass(cond_type, Number):
raise TypeError, \
- "Cond %s is of type %s, but must be a bool or Relational" \
- % (cond, cond_type)
+ "Cond %s is of type %s, but must be a bool,"\
+ " Relational or Number" % (cond, cond_type)
# Check for situations where we can evaluate the Piecewise object.
# 1) Hit an unevaluatable cond (e.g. x<1) -> keep object
@@ -88,23 +93,11 @@
return None
def doit(self, **hints):
- new_ecpairs = []
- for expr, cond in self.args:
- if hasattr(expr,'doit'):
- new_expr = expr.doit(**hints)
- else:
- new_expr = expr
- if hasattr(cond,'doit'):
- new_cond = cond.doit(**hints)
- else:
- new_cond = cond
- new_ecpairs.append( (new_expr, new_cond) )
- return Piecewise(*new_ecpairs)
+ return Piecewise(*[(e.doit(), c.doit()) for e, c in self.args])
def _eval_integral(self,x):
from sympy.integrals import integrate
- return Piecewise(*[(integrate(expr, x),cond) \
- for expr, cond in self.args])
+ return Piecewise(*[(integrate(e, x), c) for e, c in self.args])
def _eval_interval(self, sym, ab):
"""Evaluates the function along the sym in a given interval ab"""
@@ -124,7 +117,7 @@
# - eg x < 1, x < 3 -> [oo,1],[1,3] instead of [oo,1],[oo,3]
# 3) Sort the intervals to make it easier to find correct exprs
for expr, cond in self.args:
- if type(cond) == bool:
+ if issubclass(type(cond),Number):
if cond:
default = expr
break
@@ -186,45 +179,24 @@
return mul * ret_fun
def _eval_derivative(self, s):
- return Piecewise(*[(diff(expr,s),cond) for expr, cond in self.args])
+ return Piecewise(*[(diff(e, s), c) for e, c in self.args])
def _eval_subs(self, old, new):
if self == old:
return new
- new_ecpairs = []
- for expr, cond in self.args:
- if hasattr(expr,"subs") and not isinstance(expr,FunctionClass):
- new_expr = expr.subs(old, new)
- else:
- new_expr = expr
- if hasattr(cond,"subs"):
- new_cond = cond.subs(old, new)
- else:
- new_cond = cond
- new_ecpairs.append( (new_expr, new_cond) )
- return Piecewise(*new_ecpairs)
+ return Piecewise(*[(e._eval_subs(old, new), c._eval_subs(old, new)) \
+ for e, c in self.args])
@classmethod
def __eval_cond(cls, cond):
- """
- Returns if the condition is True or False.
-
- If it is undeterminable, returns None.
- """
- if type(cond) == bool:
- return cond
+ """Returns S.One if True, S.Zero if False, or None if undecidable."""
+ if issubclass(type(cond), Number) or type(cond) == bool:
+ return sympify(bool(cond))
arg0 = cond.args[0]
arg1 = cond.args[1]
if isinstance(arg0, FunctionClass) or isinstance(arg1, FunctionClass):
return None
- if hasattr(arg0,'evalf'):
- arg0 = arg0.evalf()
- if not issubclass(type(arg0),Number) and \
- type(arg0) != int and type(arg0) != float:
+ if not issubclass(type(arg0.evalf()), Number) or \
+ not issubclass(type(arg1.evalf()), Number):
return None
- if hasattr(arg1,'evalf'):
- arg1 = arg1.evalf()
- if not issubclass(type(arg1),Number) and \
- type(arg1) != int and type(arg1) != float:
- return None
- return bool(cond)
+ return sympify(bool(cond))
diff -r 2bd730295d9f -r 6422f5d608d2
sympy/functions/elementary/tests/test_piecewise.py
--- a/sympy/functions/elementary/tests/test_piecewise.py Sun Oct 19
20:26:03 2008 +0200
+++ b/sympy/functions/elementary/tests/test_piecewise.py Sun Oct 19
21:41:36 2008 +0200
@@ -35,11 +35,7 @@
dp = Piecewise((0, x < -1), (2*x, x < 0), (1/x, x >= 0))
fp_dx = x*dp + p
assert diff(p,x) == dp
- # FIXME: Seems that the function derivatives are flipping the args.
- # assert diff(f*p,x) == fp_dx
- # Test args for now.
- assert fp_dx.args[0] == diff(f*p,x).args[1]
- assert fp_dx.args[1] == diff(f*p,x).args[0]
+ assert diff(f*p,x) == fp_dx
# Test simple arithmetic
assert x*p == fp
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