skbio.diversity.alpha.
chao1
(counts, bias_corrected=True)[source]¶Calculate chao1 richness estimator.
State: Experimental as of 0.4.0.
Uses the bias-corrected version unless bias_corrected is False
and
there are both singletons and doubletons.
counts (1-D array_like, int) – Vector of counts.
bias_corrected (bool, optional) – Indicates whether or not to use the bias-corrected version of the
equation. If False
and there are both singletons and doubletons,
the uncorrected version will be used. The biased-corrected version will
be used otherwise.
Computed chao1 richness estimator.
double
See also
Notes
The uncorrected version is based on Equation 6 in 1:
where \(F_1\) and \(F_2\) are the count of singletons and doubletons, respectively.
The bias-corrected version is defined as
References
Chao, A. 1984. Non-parametric estimation of the number of classes in a population. Scandinavian Journal of Statistics 11, 265-270.