Class Pfqn_mci
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Method Summary
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Method Details
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pfqn_mci
Monte Carlo integration for the normalizing constant.Variants:
mci,imci(improved),amci,lhsmciandrm(repairman).amciandlhsmciuse theimcitilt and differ only in how the uniforms are drawn.amcidraws ANTITHETIC pairs (u, 1-u). This does NOT reliably reduce variance here: the tilted integrand is not monotone in the exponential draws (the tilt term -(1-gamma)V decreases while the N log(VD+Z) term increases), so the pair correlation is not systematically negative; measured variance ratios againstimcirange from 0.54 to 1.6 across models. It is kept because it is the Ross-Wang construction, not because it is the better default.lhsmcistratifies each coordinate by Latin hypercube sampling, which IS reliably variance-reducing on the same models (ratios 0.0 to 0.48, exact quadrature in the limit of one station) at O(I log I) extra cost.- Parameters:
D- service demand matrix (M x R)N- population vector (1 x R)Z- think time vector (1 x R)I- number of samplesvariant- sampling variant- Returns:
- the normalizing constant and its logarithm
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