Figure for autocorrelations:
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Measured integrated autocorrelations time set to tau_int=1.

Plot 5% and 15% upper bounds, tau_int(0.05) and tau_int(0.15),
as function of N_meas = (time series length) / (measured tau_int).

Note that there are two solutions! Use N=2, 3 and look at
the errors of the error bars, sigma_exact/sigma_min, etc.

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Gaussian updating and replica exchange.

MUMA Potts/Ising. XY and O(n) cluster.