Any recommendation to fix no method matching pdf?

[Etwari3]

MethodError: no method matching pdf(::Array{Float64, 3}, ::String)

[zsunberg]

This means that the solver is trying to evaluate the probability of a particular string in an array of floats.

This error is likely caused by returning an array of Floats instead of a Distribution object in transition, observation or initialstate. Judging by the error, it seems like your states are Strings. So instead of something like

return [0.1, 0.2, 0.7]

you should use a distribution object such as a 'SparseCat'

return SparseCat(["a", "b", "c"], [0.1, 0.2, 0.7])

in your transition, observation, and initialstate functions.

Side note: for future questions, it may be more helpful to post in the discussions section of POMDPs.jl https://github.com/JuliaPOMDP/POMDPs.jl/discussions rather than as an issue in this particular solver.

[zsunberg]

(I migrated this to a POMDPs.jl issue to concentrate as much knowledge as possible)

[Etwari3]

Thank you.

My apologies for the misplacement of the question.

[Etwari3]

Converted all (transition, observation, and initialstates function) to SparseCat and still did not work.

What does POMDPs.pdf function is used for? I noticed it in both 'Simple Grid World' model and the fixhorizon.jl. I could not find it in the documentation.

Thank you.

[zsunberg]

It is the same as Distributions.pdf: https://juliapomdp.github.io/POMDPs.jl/stable/api/#Distributions.pdf

It is used by solvers to evaluate the probability of a transition or observation outcome.

e.g.

distribution = SparseCat(["a", "b"], [0.1, 0.9])
pdf(distribution, "a") # should return 0.1

[Etwari3]

Thank you.