MC-QUANTITIES: Quantities from log files relating to Monte Carlo simulation. The quantities below relating to Markov chain Monte Carlo can be obtained from log files (eg, for use in xxx-plt). Note that the generic quantities documented in quantities.doc will also be available, as will quantities specific to the particular Markov chain application being used. T Temperature used (see xxx-mc.doc, NOT from the tempering schedule) E Potential energy at end of iteration E0 Potential energy at end of iteration at inverse temperature of 0 E1 Equal to E - E0 K Kinetic energy at end of iteration H Total energy at end of iteration (sum of E and K) D[n] Change in total energy for last state proposed (up to max of n) (for Metropolis, hybrid, and multivariate slice sampling operations) i Inverse temperature being used (from the tempering schedule) I Index of current inverse temperature value in schedule j Direction of change for inverse temperature J Higher temperature for attempted transition (meaningful only if last operation in iteration was sim-temp) Q[n] Importance weight, or log of importance weight (see below) F[n] Factor for estimating ratio of normalizing constants using tempered transitions (see below). d Heatbath decay factor used in this iteration f Stepsize factor used in this iteration r Rejection rate for this iteration e Average number of evaluations per slice sampling update this iteration k Cumulative cpu usage in minutes. m Point last moved to relative to starting point m0 Point moved to relative to lowest point for spiral and double-spiral m1 Starting point relative to lowest point for spiral and double-spiral m2 Switch point for double-spiral operations m3 Equal to m0-m2 (double-spiral only) m4 Equal to m1-m2 (double-spiral only) m5 Equal to |m3|-|m4| qn Component n of position pn Component n of momentum sn Stepsize selected by application for component n None of these quantities can be used with a range; 'q', 'p', and 's' must have a modifier, 'D' and 'Q' may have a modifier, 'E' may only have a modifier of '0' or '1', the others may not have a modifier. The 'Q' quantity is the importance weight, which will always be one except during annealed importance sampling. Note that these weights might sometimes be so extreme that this value overflows or underflows. If a modifier of 0 is given to 'Q', the value is the log of the importance weight, which is much less likely to be out of bounds. If a modifier n greater than zero is given for 'Q', the value is the log of the importance weight unless that is less than -n, in which case the value is -n. The 'F' quantities are factors obtained from the last tempered transition in the iterations, which can be averaged to estimate the ratio of normalizing constants for the distribution at temperature one to that of the distribution at the highest temperature. The 'F1' quantity is based on only the first half of the tempered transition. The 'F2' quantity is based on both halves if the tempered transition is accepted, and is otherwise based on just the first half. Momenta of zero are assumed if none exist. Copyright (c) 1995-2003 by Radford M. Neal