More test fixes

Author: penelopeysm

src/mcmc/emcee.jl

@@ -35,12 +35,15 @@ end
 _get_n_walkers(e::Emcee) = e.ensemble.n_walkers
 _get_n_walkers(spl::Sampler{<:Emcee}) = _get_n_walkers(spl.alg)
 
+# Because Emcee expects n_walkers initialisations, we need to override this
+DynamicPPL.init_strategy(spl::Sampler{<:Emcee}) = fill(InitFromPrior(), _get_n_walkers(spl))
+
 function AbstractMCMC.step(
     rng::Random.AbstractRNG,
     model::Model,
     spl::Sampler{<:Emcee};
     resume_from=nothing,
-    initial_params=fill(DynamicPPL.init_strategy(spl), _get_n_walkers(spl)),
+    initial_params,
     kwargs...,
 )
     if resume_from !== nothing

src/mcmc/is.jl

@@ -51,7 +51,9 @@ struct ISContext{R<:AbstractRNG} <: DynamicPPL.AbstractContext
 end
 DynamicPPL.NodeTrait(::ISContext) = DynamicPPL.IsLeaf()
 
-function DynamicPPL.tilde_assume!!(ctx::ISContext, dist::Distribution, vn::VarName, vi)
+function DynamicPPL.tilde_assume!!(
+    ctx::ISContext, dist::Distribution, vn::VarName, vi::AbstractVarInfo
+)
     if haskey(vi, vn)
         r = vi[vn]
     else
@@ -61,3 +63,8 @@ function DynamicPPL.tilde_assume!!(ctx::ISContext, dist::Distribution, vn::VarNa
     vi = DynamicPPL.accumulate_assume!!(vi, r, 0.0, vn, dist)
     return r, vi
 end
+function DynamicPPL.tilde_observe!!(
+    ::ISContext, right::Distribution, left, vn::Union{VarName,Nothing}, vi::AbstractVarInfo
+)
+    return DynamicPPL.tilde_observe!!(DefaultContext(), right, left, vn, vi)
+end

src/mcmc/particle_mcmc.jl

@@ -144,6 +144,7 @@ function AbstractMCMC.sample(
     N::Integer;
     chain_type=DynamicPPL.default_chain_type(sampler),
     resume_from=nothing,
+    initial_params=DynamicPPL.init_strategy(sampler),
     initial_state=DynamicPPL.loadstate(resume_from),
     progress=PROGRESS[],
     kwargs...,
@@ -155,6 +156,7 @@ function AbstractMCMC.sample(
             sampler,
             N;
             chain_type=chain_type,
+            initial_params=initial_params,
             progress=progress,
             nparticles=N,
             kwargs...,
@@ -166,6 +168,7 @@ function AbstractMCMC.sample(
             sampler,
             N;
             chain_type,
+            initial_params=initial_params,
             initial_state,
             progress=progress,
             nparticles=N,