def get_R_mod(options, rho0):
    """Compute synthetic measurements over a homogeneous half-space
    """
    tomodir = tdManager.tdMan(
        elem_file=options.elem_file,
        elec_file=options.elec_file,
        config_file=options.config_file,
    )

    # set model
    tomodir.add_homogeneous_model(magnitude=rho0)

    # only interested in magnitudes
    Z = tomodir.measurements()[:, 0]

    return Z