@Christopher_Fisher I think I know what caused the Loglik surface to be wobbly in your code: parms = p modifies also p during the mapping. If you do parms = copy(p) instead, the surfaces look more like they should. Beta still shows a flat surface, with the max LL at the true value of 0.15, but values > 0.15 also have a high LL, so I can see why that is difficult for the sampler.
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