the summary of the previous sections

The standard form of the density function is specified by logdensity=log f(y;θ).

By applying "ruletheta1" to logdensity, θ can be expressed in terms of η and φ derivatives.

The cumulant function ψ(θ) can be expressed in terms of η and φ derivatives as shown in psieta.

The measure function h(y) can be expressed in terms of y and φ derivatives as shown in hinyphi.