scattering matrix method and matlab code

kindly help me out with the matlab code for solving boltzmann transport kinetic equation .
there are mainly four methods for solving this equation
1) scattering matrix method
2) spherical harmonic method
3) monte carlo method
4) relaxation time approximations

if u kindly send me the matlab codes for any of the two methods , i'll be very grateful, i urgently need the matlab codes .........
thank you