How to use associated legendre polynomials in sage?

asked 2012-10-12 01:52:12 +0200

ijpulidos
1 ●1 ●1 ●1

Hey, I'm trying to make a symbolic expression (function) that depends on associated lengendre polynomials. For this I'm using the maxima module/interface. When I do something like

maxima.assoc_legendre_p(2,0,x)

I get the correct output. But when I try something like the following

lp(l,m,x) = maxima.assoc_legendre_p(l,m,x)

and then lp(2,0,3) all I get is "assoc_legendre_p(2, 0, 3)". So it's not understanding the "assoc_legendre_p" part, it takes it as many symbols. How could I achieve this? Thanks.

PS: The actual expression is more complicated than that, but to makes thing simple I used a basic example.

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answered 2012-10-12 05:22:01 +0200

twch
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I do not really know what your intension is, but if you define your lp as a function call, then everything works fine for me:

show(maxima.assoc_legendre_p(2,0,x))
show(maxima.assoc_legendre_p(2,0,3))

and

def k(l,m,n):
    return maxima.assoc_legendre_p(l,m,n)
show(k(2,0,x))
show(k(2,0,3))

produces the same aoutput for me. Maybe this already helps you?

Honestly I didn't really understand the problem with your call. Probably maxima returns other object types when you enter symbolic expressions and it is not possible anymore to evaluate this expression. Maybe somebody else can explain us the problem...