Extensive facilities for power and sample size calculations have been added to the more recent versions of Haplin. In particular, the functions snpPower, snpSampleSize, hapPower, and hapPowerAsymp have been provided to do this for fetal effects, maternal effects, parent-of-origin effects, GxE analyses etc. Please see Haplin_power for further details.
The power calculations have been documented in
Version 7.1.0 includes the hapRelEff function, which explores relative efficiencies for various Haplin designs, to evaluate how power is affected by design. The hapRelEff vignette explains.