Function spearmanCor
Spearman's rank correlation. Non-parametric. This is essentially the Pearson correlation of the ranks of the data, with ties dealt with by averaging.
double spearmanCor(R, S)
(
R input1,
S input2
)
if (isInputRange!R && isInputRange!S && is(typeof(input1 .front < input1 .front) == bool) && is(typeof(input2 .front < input2 .front) == bool));