genlaguerre poly1d-object doesn't respect 'monic' option at evaluation

[oestfeldt]

Using Python 3.6 with Anaconda. Fresh install 2 weeks ago.

I'm using the funciton scipy.special.genlaguerre to generate the generalized laguerre polynomials. The function has the option 'monic' which scales the parameters, such that the leading parameter equals 1.

The returned poly1d-object print correctly scaled, but evaluating the function does not correspond to the printed object. The default function (non-scaled) is always returned.

MWE:
from scipy.special import genlaguerre

gl1 = genlaguerre(1,1,monic=False)
gl2 = genlaguerre(1,1,monic=True)

print(gl1)
print(gl2)

print(gl1(0))
print(gl2(0))

Output:

-1 x + 2

1 x - 2
2.0
2.0

[person142]

Problem is here:

https://github.com/scipy/scipy/blob/master/scipy/special/orthogonal.py#L130

In particular, in this block of code:

mu = sqrt(hn)
if monic:
    evf = eval_func
    if evf:
        eval_func = lambda x: evf(x) / kn
    mu = mu / abs(kn)
    kn = 1.0

It scales eval_func by kn, which is correct--but then it redefines kn = 1.0, which undoes the scaling.