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Known Problems and Solutions

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Product Version 23.1 June 2023

This Known Problems and Solutions document describes important Cadence Change Management System Change Request Records (CCRs) for Spectre Circuit Simulator and tells you how to solve or work around these problems.

CCR 1145555: Biased samples are found in sampling=orthogonal in Spectre Monte Carlo Analysis

Description: If the integration function is an even function, the orthogonal sampling algorithm may generate an underestimated variance (2nd-moment) of the output, when the number of iterations is close to the size of the orthogonal subgroups.

Solution: Increase the value of the numruns parameter to remove the bias.