The program UCSF DOCK was created in the 1980s by Irwin "Tack" Kuntz's Group, and was the first docking program. DOCK uses geometric algorithms to predict the binding modes of small molecules. Brian K. Shoichet, David A. Case, and Robert C.Rizzo are codevelopers of DOCK. Two versions of the docking program are actively developed: DOCK 6 and DOCK 3. Ligand sampling methods used by the program DOCK include. A molecular dynamics engine was implemented into DOCK v6 by David A. Case's Group in the scoring function AMBER score. This ability accounts for receptor flexibility and allows for rank ordering by energetic ensembles in the docking calculations.