  We formulate an algebraic relativistic method of scattering for systems with
spatially dependent mass based on the J-matrix method. The reference
Hamiltonian is the three-dimensional Dirac Hamiltonian but with a mass that is
position-dependent and having a constant asymptotic limit. Additionally, this
effective mass distribution is locally represented in a finite dimensional
function subspace. The spinor couples to spherically symmetric vector and
pseudo scalar potentials that are short-range such that they are accurately
represented by their matrix elements in the same finite dimensional subspace.
We calculate the relativistic phase shift as a function of energy for a given
configuration and study the effect of spatial variation of the mass on the
energy resonance structure.
