Status: New
Owner: ----
Labels: Type-Defect Priority-Medium
New issue 2128 by jagermeistermeister: cannot integrate piecewise function
numerically
http://code.google.com/p/sympy/issues/detail?id=2128
Hi,
I'm new to sympy, so please forgive me if this is not a bug :-)
I am trying to integrate the following Piecewise function over the interval
[-oo. oo]:
f = 0.0032513612725229*Piecewise((0, x < -80.8461538461539),
(1.33215984776403 - 0.0160799238820171*x, x < 2), (Piecewise((0.4, 2 < x),
(0.6, 1)) + Piecewise((0.3, 123 < x), (0.7, 1)), x <= 123),
(2.10541401273885 - 0.00817409766454352*x, x < 380.571428571429), (0, 1))
In pretty print it looks like this:
0.0032513612725229⋅⎧ 0 for x <
-80.8461538461539
⎪
⎪1.33215984776403 - 0.0160799238820171⋅x for x
< 2
⎪
⎪ ⎧0.4 for 2 < x + ⎧0.3 for 123 < x for x
≤ 123
⎨ ⎨ ⎨
⎪ ⎩0.6 otherwise ⎩0.7 otherwise
⎪
⎪2.10541401273885 - 0.00817409766454352⋅x for x <
380.571428571429
⎪
⎩ 0
otherwise
I expect the result to be a number, but it returns the following (command:
sympy.integrate(f, (x, -oo, oo)) ):
∞
⌠
⎮ 0.0032513612725229⋅x⋅⎧ 0 for x <
-80.8461538461539 dx
⎮ ⎪
⎮ ⎪1.33215984776403 - 0.0160799238820171⋅x
for x < 2
⎮ ⎪
⎮ ⎪ ⎧0.4 for 2 < x + ⎧0.3 for 123 < x
for x ≤ 123
⎮ ⎨ ⎨ ⎨
⎮ ⎪ ⎩0.6 otherwise ⎩0.7 otherwise
⎮ ⎪
⎮ ⎪2.10541401273885 - 0.00817409766454352⋅x for x <
380.571428571429
⎮ ⎪
⎮ ⎩ 0
otherwise
⌡
-∞
Which is the same function as I passed to integrate(), but with an integral
sign in front of it :)
Also, it takes quite a long time for it to give that answer, it takes about
1 second.
If this is a bug, I'm willing to help fix it. I'd need some directions,
though. I'm new to sympy and python. :) (no experience with git yet either!)
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