  We perform density-matrix renormalization group studies of a two-dimensional
electron gas in a high magnetic field and with an anisotropic band mass. At
half-filling in the lowest Landau level, such a system is a Fermi liquid of
composite fermions. By measuring the Fermi surface of these composite fermions,
we determine a relationship between the anisotropy of composite fermion
dispersion, $\alpha_{CF}$, and the original anisotropy $\alpha_F$ of the
fermion dispersion at zero magnetic field. For systems where the electrons
interact via a Coulomb interaction, we find $\alpha_{CF}=\sqrt{\alpha_F}$
within our numerical accuracy. The same result has been found concurrently in
recent experiments. We also show results with other forms of the
electron-electron interaction; this allows us (a) to benchmark our procedure
against known exact results and (b) to show that the relationship between the
anisotropies is dependent on the form of the interaction.
