EXTERNAL

SUB eclazz (nf(), n, dum)

    DECLARE FUNCTION equiv        ! Supplied by the user

    LET nf(1) = 1
    FOR jj = 2 to n
        LET nf(jj) = jj
        FOR kk = 1 to jj - 1
            LET nf(kk) = nf(nf(kk))
            IF equiv(jj, kk)=-1 then LET nf(nf(nf(kk))) = jj
        NEXT kk
    NEXT jj
    FOR jj = 1 to n
        LET nf(jj) = nf(nf(jj))
    NEXT jj

END SUB