bhattacharyya(...)
"bhattacharyya"(enma, covs=NULL, ncore=NULL, ...)
"bhattacharyya"(covs, ncore=NULL, ...)
"bhattacharyya"(a, b, q=90, n=NULL, ...)
"bhattacharyya"(...)
"bhattacharyya"(...)"enma" obtained from function
    nma.pdbs. ncore>1 requires package parallel installed. b. a. sip, covsoverlap, rmsip.