Interpolate linear power on the ratio against an analytic formula.

[rainwoodman]

This may be more robust against resolution effects of the input table file.

Computer difference of interpolated linear power against a high res input table file and a low res input table file.
If there is improvement we shall be able to see it.

There is an EH power transfer function formula in nbodykit that we can take.

[rainwoodman]

Probably better to switch to a cubic spline instead, as it performs better when trying to match a CLASS power spectrum (which may also uses cubic spline interpolation)