[SciPy-user] Using scipy specfunc in integration

Neal Becker ndbecker2@gmail....
Sat Jun 14 16:57:07 CDT 2008


Anne Archibald wrote:

> 2008/6/13 Robert Kern <robert.kern@gmail.com>:
>> On Fri, Jun 13, 2008 at 09:21, Neal Becker <ndbecker2@gmail.com> wrote:
>>> Any ideas on this?
>>> from scipy.special import erf
>>> from math import exp, tan
>>> def cot(x):
>>>    return 1/tan(x)
>>>
>>> N = 8
>>> esnodB = 10
>>> Rd = 10**(.1 * esnodB)
>>>
>>> def F (y):
>>>    return exp (-(y**2)) * erf (y * cot (pi/N))
>>>
>>>
>>> Pe = float(N-1)/float(N) - 0.5 * erf (sqrt (Rd * sin (pi/N))) -
>>> 1/(sqrt(pi)) * quadrature(F, 0, sqrt(Rd) * sin (pi/N))[0]
>>> TypeError: only length-1 arrays can be converted to Python scalars
>>>
>>> It seems to be complaining about erf.
>>> erf
>>> Out[33]: <ufunc 'erf'>
>>
>> I think it's complaining about exp(), actually. quadrature() is going
>> to pass arrays to F(), not scalars.
> 
> Specifically, math.exp and math.tan do not accept vector arguments;
> don't use them. Use numpy.exp and numpy.tan instead.
> 
> Anne
Thanks, but I'm confused.  The above code is strictly scalar - who's asking
for vectors?



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