  We describe a method for the numerical computation of the propagation of
primary and secondary nucleons, primary electrons, and secondary positrons and
electrons. Fragmentation and energy losses are computed using realistic
distributions for the interstellar gas and radiation fields, and diffusive
reacceleration is also incorporated. The models are adjusted to agree with the
observed cosmic-ray B/C and 10Be/9Be ratios. Models with diffusion and
convection do not account well for the observed energy dependence of B/C, while
models with reacceleration reproduce this easily. The height of the halo
propagation region is determined, using recent 10Be/9Be measurements, as >4 kpc
for diffusion/convection models and 4-12 kpc for reacceleration models. For
convection models we set an upper limit on the velocity gradient of dV/dz < 7
km/s/kpc. The radial distribution of cosmic-ray sources required is broader
than current estimates of the SNR distribution for all halo sizes. Full details
of the numerical method used to solve the cosmic-ray propagation equation are
given.
