def arcsine_sqrt_transform(rel_abd):
arcsint = lambda p: math.asin(math.sqrt(p))<EOL>return {col_id: {row_id: arcsint(rel_abd[col_id][row_id])<EOL>for row_id in rel_abd[col_id]} for col_id in rel_abd}<EOL>
Takes the proportion data from relative_abundance() and applies the
variance stabilizing arcsine square root transformation:

X = sin^{-1} \sqrt p