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Monte Carlo Analysis<br />

Importance Sampling Monte Carlo Examples<br />

follows a binomial law with parameters (n, π y ). Since S n is the sum of independent Bernouilli<br />

random variables with parameter π y (such that<br />

), the central limit theorem<br />

gives:<br />

where<br />

At a confidence level α, the precision ε can be related to the sample size via 2Φ(-t) ≤ α. The<br />

number of Monte Carlo simulations is:<br />

In terms of the relative precision (the IS_RTOL parameter in the .MC statement) τ > 0, the<br />

number of Monte Carlo simulations is:<br />

because ε = τπ y .<br />

The reported speedup can be calculated by replacing τ by the effective relative precision<br />

obtained for the estimator. This value is given in the CV(%) column of the results. The ratio<br />

n MC / n ISMC then gives the speedup, where n ISMC is the effective number of runs.<br />

Table 11-1 displays the results of an experiment that can be carried out using this example. The<br />

value of IS_MAXITER is 50 to limit the total number of Monte Carlo runs. The ISMC method<br />

only failed to reach the desired precision within 50 iterations in the last experiment (1% RTOL).<br />

Eldo® User's Manual, 15.3 529

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