#2452: [with patch, needs work] Heaviside step function, Dirac delta needed
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Reporter: gfurnish | Owner: gfurnish
Type: enhancement | Status: assigned
Priority: major | Milestone: sage-4.1
Component: symbolics | Keywords:
Reviewer: | Author:
Merged: |
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Comment(by burcin):
Hi Golam,
You're right! When using high precision we start calling maxima to decide
if two expressions are equal. This kills performance as you observed.
Now I suggest using `CIF(x).imag() == 0` where `x` is the element you want
to test for. This is consistent in timings, and produces correct results:
{{{
sage: u = 1 + I*exp(-10000000000000000)
sage: CIF(u).imag() == 0
False
sage: timeit('b = (CIF(u).imag() == 0)')
625 loops, best of 3: 761 µs per loop
sage: t = 1 + I*exp(-10000)
sage: CIF(t).imag() == 0
False
sage: timeit('b = (CIF(t).imag() == 0)')
625 loops, best of 3: 784 µs per loop
}}}
Thanks.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/2452#comment:17>
Sage <http://sagemath.org/>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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