Bray-Curtis beta diversity metric

See also
beta_div command
Beta diversity metrics

The Bray-Curtis metric between samples i and j is calculated as follows.

N = number of OTUs.

n _ki = count of OTU k in sample i .

S = sum k = 1 .. N of min ( n _ki , n _kj )

T = sum k = 1 .. N of ( n _ki + n _kj )

Bray-Curtis = 1 - 2 S / T