I tried to look for this bug and haven't found it (maybe my lacking search 
skills), still I felt uncomfortable to open an issue. 

Here is the code:

x=Symbol("x")

f1=2*E**(-2*x)
F1=integrate(f1,(x,0,oo))
print F1 #Works great:

a=Symbol("a")
f2=abs(a)*E**(-abs(a)*x)
F2=integrate(f2,(x,0,oo)) #fails

and the output is:

Traceback (most recent call last):
  File "C:/Users/Barak/Desktop/python/temp", line 18, in <module>
    F2=integrate(f2,(x,0,oo))
  File "C:\Python27\lib\site-packages\sympy\utilities\decorator.py", line 
24, in threaded_func
    return func(expr, *args, **kwargs)
  File "C:\Python27\lib\site-packages\sympy\integrals\integrals.py", line 
847, in integrate
    return integral.doit(deep = False)
  File "C:\Python27\lib\site-packages\sympy\integrals\integrals.py", line 
393, in doit
    function = antideriv._eval_interval(x, a, b)
  File "C:\Python27\lib\site-packages\sympy\core\expr.py", line 229, in 
_eval_interval
    B = limit(self, x, b)
  File "C:\Python27\lib\site-packages\sympy\series\limits.py", line 116, in 
limit
    return i*limit(d, z, z0, dir)
  File "C:\Python27\lib\site-packages\sympy\series\limits.py", line 192, in 
limit
    r = gruntz(e, z, z0, dir)
  File "C:\Python27\lib\site-packages\sympy\series\gruntz.py", line 678, in 
gruntz
    r = limitinf(e, z)
  File "C:\Python27\lib\site-packages\sympy\core\cache.py", line 101, in 
wrapper
    func_cache_it_cache[k] = r = func(*args, **kw_args)
  File "C:\Python27\lib\site-packages\sympy\series\gruntz.py", line 480, in 
limitinf
    c0, e0 = mrv_leadterm(e, x)
  File "C:\Python27\lib\site-packages\sympy\core\cache.py", line 101, in 
wrapper
    func_cache_it_cache[k] = r = func(*args, **kw_args)
  File "C:\Python27\lib\site-packages\sympy\series\gruntz.py", line 562, in 
mrv_leadterm
    f, logw = rewrite(exps, Omega, x, w)
  File "C:\Python27\lib\site-packages\sympy\series\gruntz.py", line 627, in 
rewrite
    raise NotImplementedError('Result depends on the sign of %s' % sig)
NotImplementedError: Result depends on the sign of -sign(Abs(a))


-- 
You received this message because you are subscribed to the Google Groups 
"sympy" group.
To view this discussion on the web visit 
https://groups.google.com/d/msg/sympy/-/W6WpoV5C5DUJ.
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?hl=en.

Reply via email to