[SciPy-user] symbolic math & scipy (& swiginac)

fred fredantispam at free.fr
Tue Aug 8 06:22:11 CDT 2006


fred a écrit :
> Jelle Feringa / EZCT Architecture & Design Research a écrit :
> 
>>http://swiginac.berlios.de/
>>
>>could be interesting for dealing with symbolic computation
> 
> Ok, sounds good...
> 
> But I did not find anything about Legendre associated polynomials. :-(
One can try to define them :

from scipy.special import *
from swiginac import *

x = symbol('x')

def lpm(m,x):
    p = (x**2-1)**m
    return (1./(2**m*factorial(m))*p.diff(x,m))

def lpmn(m,n,x):
    p = lpm(n,x)
    return ((-1)**m*(1-x**2)**(m/2.)*p.diff(x,m))

print lpm(2,x)

>>>-0.5+(1.5)*x**2
Ok.

But :

u = arange(0,1,0.1)
print lpm(2,u)

Traceback (most recent call last):
  File "./essai.py", line 20, in ?
    print lpm(2,u)
  File "./essai.py", line 11, in lpm
    return (1./(2**m*factorial(m))*p.diff(x,m))
AttributeError: 'numpy.ndarray' object has no attribute 'diff'

Any suggestion ?

Cheers,

-- 
Fred.


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