Generate pda UWZ derivatives
ODAC.derive(ipdata, control, config)
list(T_all=T_all, b_meta=b_meta, site=control$mysite, site_size = nrow(ipdata), U=U, W=W, Z=Z, logL_D1=logL_D1, logL_D2=logL_D2)
individual participant data
pda control data
local site configuration
Calculate and broadcast 1st and 2nd order derivative at initial bbar for ODAC, this requires 2 substeps: 1st calculate summary stats (U, W, Z), 2nd calculate derivatives (logL_D1, logL_D2)