Fix HierarchicalDistributions w/ dof smaller than length

[waldie11]

For some distributions length and dof do not coincide. This enables usage of e.g. Dirichlet distributions in HierarchicalDistributions

[waldie11]

Example:

using BAT
using ValueShapes
using Distributions
using InverseFunctions

d = HierarchicalDistribution(NamedTupleDist(
       a=truncated(Logistic(),0,Inf),
)) do v
       NamedTupleDist(
             b=Dirichlet(10,1/v.a),
       )
end

inverse(BAT.DistributionTransform(Normal,d))(zeros(1+9))

[oschulz]

Thanks!

[waldie11]

With pleasure :wink: