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Last modified: 11 October 2018

URL: http://cxc.harvard.edu/ciao/bugs/aprates.html

Bugs: aprates


Caveats

# aprates (CIAO): WARNING: Large number of counts, just using Gaussian pdf

For low counts, aprates uses Poisson statistics, but for moderately large n or m (100's), this takes a very long time. If pdf=alternate, the tool uses the max_counts parameter to determine when to take an alternate path and use Gaussian statistics.

The quantity (rn-m)/(rf-g), which is the solution for net counts S in the set of simultanaeous linear equations given in the help file, is used to determine the transition between Bayesian and Gaussian approaches for the max_counts parameter.