Create a compact show for MvNormal.

[Vilin97]

Create an MvNormal distribution:

julia> using LinearAlgebra, Distributions

julia> dist = MvNormal(I(2)) # plaintext unchanged
MvNormal{Bool, PDMats.PDiagMat{Bool, Vector{Bool}}, FillArrays.Falses{1, Tuple{Base.OneTo{Int64}}}}(
dim: 2
μ: Zeros{Bool}(2)
Σ: Bool[1 0; 0 1]
)

Before:

julia> "$dist"
"MvNormal{Bool, PDMats.PDiagMat{Bool, Vector{Bool}}, FillArrays.Falses{1, Tuple{Base.OneTo{Int64}}}}(\ndim: 2\nμ: Zeros{Bool}(2)\nΣ: Bool[1 0; 0 1]\n)\n"

After:

julia> "$dist" # nice compact representation
"MvNormal(Zeros{Bool}(2), Bool[1 0; 0 1])"

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Files	Coverage Δ
src/multivariate/mvnormal.jl	73.59% <50.00%> (-4.39%)	⬇️

... and 133 files with indirect coverage changes

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[Vilin97]

@devmotion , I'm not sure who is the right person to ping, sorry.
Let me know if this is a kind of change that you would be open to. This closes my issue #1785.

[devmotion]

There's already a show_oneline implementation in Distributions for compact representation. IMO it should actually be the default for show(io, dist), and only show(io, ::MIME"text/plain", dist) should use the current path which returns a one- or multiline representation depending on the number of parameters.

So I wonder what the implications of changing

Distributions.jl/src/show.jl

Line 12 in e407fa5

show(io::IO, d::Distribution) = show(io, d, fieldnames(typeof(d)))

to

show(io::IO, d::Distribution) = show_oneline(io, d, fieldnames(typeof(d)))
show(io::IO, ::MIME"text/plain", d::Distribution) = show(io, d, fieldnames(typeof(d)))

would be.

[Vilin97]

show_oneline looks messy. Compare the two:

julia> "$dist" # show_oneline
"MvNormal{Bool, PDMats.PDiagMat{Bool, Vector{Bool}}, FillArrays.Falses{1, Tuple{Base.OneTo{Int64}}}}(dim=2, μ=Zeros{Bool}(2), Σ=Bool[1 0; 0 1])"

julia> "$dist" # the new show method
"MvNormal(Zeros{Bool}(2), Bool[1 0; 0 1])"

[devmotion]

Yeah, maybe the type parameters should be omitted in show_oneline. Additionally, I don't think you'd want to add the dim output to MvNormal, the vanilla show_oneline with the fields should be sufficient.