Just a quick question. If you sample multiple chains from your model, do standard functions from arviz like az.plot_posterior (used to plot posterior), az.hdi (used to construct highest density interval) use samples from all the chains, or just one of the chains (for example the first)?
I did a quick sanity check where I sampled two chains of very few samples (like 2 chains of 10 samples) and az.plot_posterior plotted a bimodal distribution from that, so it looks like the arviz functions are using all the chains, but I thought I’d ask just to double check.