API reference¶
Gravitytype spatial interaction models¶

Base class to set up gravitytype spatial interaction models and dispatch estimaton technqiues. 

Unconstrained (traditional gravity) gravitytype spatial interaction model 

Productionconstrained (originconstrained) gravitytype spatial interaction model 

Attractionconstrained (destinationconstrained) gravitytype spatial interaction model 

Doublyconstrained gravitytype spatial interaction model 
Tests for overdispersion¶

Test the hypothesis that var[y] = mu (equidispersion) against the alternative hypothesis that var[y] = mu + alpha * alt_var(mu) where mu is the expected value of y, alpha is an estimated coefficient, and alt_var() specifies an alternative variance as a function of mu. 

Test the hypothesis that var[y] = mu (equidispersion) against the alternative hypothesis (quasiPoisson) that var[y] = phi * mu where mu is the expected value of y and phi is an estimated overdispersion coefficient which is equivalent to 1+alpha in the alternative alpha dispersion test. 