I am trying to do an inverse laplace transformation of a relative simple 
filter, but have found that it does not take much before the transformation 
takes forever.

I wonder if there is something wrong in my configuration.   Windows 
7 WinPython-32bit-2.7.6.4

I started to strip out terms in my filter to see when Sympy could compute a 
result.

When I try just the real filter (last calculation), the memory footprint 
keeps growing. I stopped it at 2G.

Any ideas


from sympy import *
from sympy.abc import s,t
from datetime import datetime

startTime = datetime.now()
H = 1/(258.0*s + 1100000.)
inverse_laplace_transform(1/s*H,s,t)
print "1) ",datetime.now() - startTime                   * #my computer 
takes 0.3sec*

startTime = datetime.now()
H = 1/(0.07071*s**2 + 258.0*s + 1100000.)
inverse_laplace_transform(1/s*H,s,t)
print "2) ",datetime.now() - startTime                    *# 55 minutes and 
still no solution.... Memory usage: 50Meg*

startTime = datetime.now()
H = 1/(7.896e-6*s**3 + 0.07071*s**2 + 258.0*s + 1100000.)
inverse_laplace_transform(1/s*H,s,t)
print "3) ",datetime.now() - startTime

#Real filter
startTime = datetime.now()
H = (0.05*s + 1000.0)**2/(2.209e-10*s**4 + 7.896e-6*s**3 + 0.07071*s**2 + 
258.0*s + 1100000.)
inverse_laplace_transform(1/s*H,s,t)
print "4) ",datetime.now() - startTime

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