The main program sets up geometry of solution domain.

• The solution domain can be either 1-D or 2-D.
• In 1-D, Source term and conductivity term can be described analytically using polynomials.
• Option to solve using Finite Differences is now implemented.

• Boundary conditions are applied on half-volumes, such that nodes are on boundaries, as described in Patankar.
• S_p Source Tester let's you try solutions with positive or negative S_p and see how solutions match analytical expectations (or not).

solve.m solves the resulting system of linear equations.