API reference¶
Gravity-type spatial interaction models¶
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Base class to set up gravity-type spatial interaction models and dispatch estimaton technqiues. |
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Unconstrained (traditional gravity) gravity-type spatial interaction model |
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Production-constrained (origin-constrained) gravity-type spatial interaction model |
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Attraction-constrained (destination-constrained) gravity-type spatial interaction model |
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Doubly-constrained gravity-type spatial interaction model |
Tests for overdispersion¶
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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. |
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Test the hypothesis that var[y] = mu (equidispersion) against the alternative hypothesis (quasi-Poisson) 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. |