[SciPy-Dev] stats.hypsecant2

[josef.pktd at gmail.com]

On Thu, Feb 1, 2018 at 11:15 PM, Andrew Nelson <andyfaff at gmail.com> wrote:

> Does anyone have any objections to adding a secant-squared distribution to
> stats?
> The CDF of this distribution (hyperbolic tangent) is frequently used for
> modelling scattering data (see appendix A in https://doi.org/10.1107/
> S1600576717013632, eqns 25 and 26).
>
> CDF = 0.5 * {1 + tanh(pi * (x - loc) / 2 / sqrt(3) / scale)}
> PDF = (pi / 4 / sqrt(3) / scale) * (cosh(pi * (x - loc) / 2 / sqrt(3) /
> scale))**-2
>
> I'm guessing the name should be hypsecant2
>

wikipedia redirects me to logistic distribution
https://en.wikipedia.org/wiki/Logistic_distribution

Can you check if it's the same?
That seems to be the case based on the cdf

Josef


>
> Andrew.
>
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