Status: Accepted
Owner: ----
CC: [email protected]
Labels: Type-Defect Priority-Medium Integration WrongResult
New issue 3023 by [email protected]: integrate(exp(-I*x**2), (x, -oo, oo))
is wrong!
http://code.google.com/p/sympy/issues/detail?id=3023
This took a lot of grief before I figured it out. I couldn't figure out
where I was dropping the minus sign.
In [138]: integrate(exp(-I*x**2), (x, -oo, oo))
Out[138]:
-3⋅ⅈ⋅π
──────
___ 4
-ⅈ⋅╲╱ π ⋅ℯ
In [139]: integrate(exp(-I*x**2), (x, -oo, oo)).evalf()
Out[139]: -1.2533141373155 + 1.2533141373155⋅ⅈ
The correct answer should be the negative of that.
http://www.wolframalpha.com/input/?i=integrate(exp(-I*x**2)%2C+(x%2C+-oo%2C+oo)).
Something like integrate(exp(-I*(k*sqrt(t) + x/(2*sqrt(t)))**2 +
x**2/(4*t)), (k, -oo, oo), conds='none').simplify() is computed correctly,
but if you replace the stuff inside the square with a new integration
variable, it doesn't work.
(Unrelated note, if you pull out the exp(x**2/(4*t)) from the integrand, it
can still do it, but simplify() cannot reduce it to something nice unless
that is included. I guess I'll open a new issue for that).
--
You received this message because you are subscribed to the Google Groups
"sympy-issues" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sympy-issues?hl=en.
