A three-dimensional collisionless code is used to simulate the formation of elliptical galaxies with a time scale for star formation comparable to the collapse time. A one-zone chemical evolution scheme is used to compute the evolution of the abundances of several chemical elements. The initial clumpy system is made of gas and, in some cases, of warm dark matter. In the latter case, it is shown that abundance gradients are produced. For a galaxy of 10 11 M ⊙ of gas and 3 × 10 11 M ⊙ of warm dark matter, the predicted gradients of Fe and Mg are d[Fe/H]/d(log r) = −0.11 and d[Mg/H]/d(log r) = −0.05, respectively