We report atomistic simulations of In x Ga 1 - x As/GaAs quantum dots (QDs) with nonuniform composition. The Tersoff potential is used to model the atomic interactions of an inhomogeneous system of 400 000 atoms and to obtain dynamic relaxation through energy minimization, From the relaxed atomistic model, the bond deformations are analyzed in order to predict the strain maps. The same technique is also employed to model the strain relaxation of a cleaved QD, allowing us to study the loss of planarity of the cleavage surface and to compare this with experimental scanning tunneling microscopy results. We confirm that an inverted pyramid-like In composition is likely to generate the topographical maps previously reported.