Various fixes and expounding on differing parts.
Various fixes and expounding on differing parts.

chunshen1987/DistributionSampling,chunshen1987/DistributionSampling,chunshen1987/DistributionSampling,chunshen1987/DistributionSampling,chunshen1987/DistributionSampling,chunshen1987/DistributionSampling