Regionalization: A method for generating joint density estimates

Regionalization is a method by which the joint probability density for two or more jointly distributed random variables can be estimated when only their respective frequency distributions or intervariable tracking specifications are known. The method can be used to improve the performance of circuit analysis programs in two ways: by weighting the samples to reduce the number of trials required for a statistical analysis, and by partitioning the output space in order to determine the input combinations that are most likely to cause failure.