details: http://hg.sympy.org/sympy/rev/8d7fc8ac251a
changeset: 1847:8d7fc8ac251a
user: Andy R. Terrel <[EMAIL PROTECTED]>
date: Wed Oct 22 22:39:07 2008 +0200
description:
Move evaluation of interval to _eval_interval method of Basic. Allows for
functions to override for integration with limits.
diffs (120 lines):
diff -r 95089a89cabd -r 8d7fc8ac251a sympy/core/basic.py
--- a/sympy/core/basic.py Wed Oct 22 22:13:34 2008 +0200
+++ b/sympy/core/basic.py Wed Oct 22 22:39:07 2008 +0200
@@ -1123,6 +1123,31 @@
if e.has(p):
return True
return False
+
+ def _eval_interval(self, x, a, b):
+ """
+ Returns evaluation over an interval. For most funtions this is:
+
+ self.subs(x, b) - self.subs(x, a),
+
+ possibly using limit() if NaN is returned from subs.
+
+ """
+ from sympy.series import limit
+ A = self.subs(x, a)
+
+ if A is S.NaN:
+ A = limit(self, x, a)
+ if A is S.NaN:
+ return self
+
+ B = self.subs(x, b)
+
+ if B is S.NaN:
+ B = limit(self, x, b)
+ if B is S.NaN:
+ return self
+ return B - A
def _eval_power(self, other):
return None
diff -r 95089a89cabd -r 8d7fc8ac251a sympy/functions/elementary/piecewise.py
--- a/sympy/functions/elementary/piecewise.py Wed Oct 22 22:13:34 2008 +0200
+++ b/sympy/functions/elementary/piecewise.py Wed Oct 22 22:39:07 2008 +0200
@@ -116,14 +116,13 @@
from sympy.integrals import integrate
return Piecewise(*[(integrate(e, x), c) for e, c in self.args])
- def _eval_interval(self, sym, ab):
+ def _eval_interval(self, sym, a, b):
"""Evaluates the function along the sym in a given interval ab"""
# FIXME: Currently only supports conds of type sym < Num, or Num < sym
int_expr = []
- a, b = ab
mul = 1
if a > b:
- a = ab[1]; b = ab[0]; mul = -1
+ a, b, mul = b, a, -1
default = None
# Determine what intervals the expr,cond pairs affect.
@@ -179,20 +178,9 @@
", ".join([str((h[0], h[1])) for h in holes])
# Finally run through the intervals and sum the evaluation.
- # TODO: Either refactor this code or Integral.doit to call
_eval_interval
ret_fun = 0
for int_a, int_b, expr in int_expr:
- B = expr.subs(sym, min(b,int_b))
- if B is S.NaN:
- B = limit(expr, sym, min(b,int_b))
- if B is S.NaN:
- return self
- A = expr.subs(sym, max(a,int_a))
- if A is S.NaN:
- A = limit(expr, sym, max(a,int_a))
- if A is S.NaN:
- return self
- ret_fun += B - A
+ ret_fun += expr._eval_interval(sym, max(a, int_a), min(b, int_b))
return mul * ret_fun
def _eval_derivative(self, s):
diff -r 95089a89cabd -r 8d7fc8ac251a
sympy/functions/elementary/tests/test_piecewise.py
--- a/sympy/functions/elementary/tests/test_piecewise.py Wed Oct 22
22:13:34 2008 +0200
+++ b/sympy/functions/elementary/tests/test_piecewise.py Wed Oct 22
22:39:07 2008 +0200
@@ -49,7 +49,7 @@
f2 = x*y**2 + 3
peval = Piecewise( (f1, x<0), (f2, x>0))
peval_interval = f1.subs(x,0) - f1.subs(x,-1) + f2.subs(x,1) - f2.subs(x,0)
- assert peval._eval_interval(x,(-1,1)) == peval_interval
+ assert peval._eval_interval(x, -1, 1) == peval_interval
# Test integration
p_int = Piecewise((-x,x < -1), (x**3/3.0, x < 0), (-x + x*log(x), x >= 0))
diff -r 95089a89cabd -r 8d7fc8ac251a sympy/integrals/integrals.py
--- a/sympy/integrals/integrals.py Wed Oct 22 22:13:34 2008 +0200
+++ b/sympy/integrals/integrals.py Wed Oct 22 22:39:07 2008 +0200
@@ -132,26 +132,8 @@
if ab is None:
function = antideriv
else:
- if isinstance(antideriv,Piecewise):
- function = antideriv._eval_interval(x,ab)
- continue
-
a,b = ab
- A = antideriv.subs(x, a)
-
- if A is S.NaN:
- A = limit(antideriv, x, a)
- if A is S.NaN:
- return self
-
- B = antideriv.subs(x, b)
-
- if B is S.NaN:
- B = limit(antideriv, x, b)
- if B is S.NaN:
- return self
-
- function = B - A
+ function = antideriv._eval_interval(x, a, b)
return function
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