initial_state is not used when resume_from is not specified #2679
Description
sample does not use initial_state if specified without resume_from. EDIT: This applies when sampler is of type Sampler{<:AdaptiveHamiltonian}.
I encountered this when I tried to resume one chain after running multiple chains, and thought I'd do this using initial_state instead of resume_from, especially in light of #2675.
MWE:
using Turing, Random
@model function gdemo(x)
s² ~ InverseGamma(2, 3)
m ~ Normal(0, sqrt(s²))
for i in eachindex(x)
x[i] ~ Normal(m, sqrt(s²))
end
end
rng = Random.default_rng();
Random.seed!(rng, 1);
data = 4 .+ 0.1 .* randn(rng, 100);
chain1 = sample(rng, gdemo(data), NUTS(), 10, nadapts=1000, save_state=true)
display(Array(chain1))
chain2 = sample(rng, gdemo(data), NUTS(), 10, nadapts=0, initial_state=chain1.info.samplerstate)
display(Array(chain2)) # initial params is drawn from prior instead of using initial_state