Figure 2.

Two-dimensional slices of the parameter landscape computed by numerically evaluating the ln(posterior) over a dense set of grid points on a two-dimensional space. Superimposed in green, red and blue are MCMC walks with varying step numbers and with (left) or without Hessian-guidance (right). (A) With Hessian guidance, the longer chains of 5000 and 10 000 steps (red and green, respectively) converged by the Gelman–Rubin criterion. (B) Without Hessian guidance, none of the three chains converged. The other 76 parameter values were kept constant for this analysis.