On Mon, Jul 6, 2009 at 1:47 PM, Priit Laes<[email protected]> wrote: > > Hey! > > While trying to implement method of characteristics, I ran into a > following problem: > > I get (choose) following system of characteristic equations as a > solution for PDE [ D(u(x, t), t) + a*D(u(x, t), x) == 0 ]: > > dx/ds = a ; dt/ds = 1 ; dz/ds = 0 > > Now, after solving these equations I have a system of three equations, > from where I have to eliminate the parameter s: > x(s) = a*z+C1 ; t(s) = s + C2 ; z(s) = C3 > C1, C2, C3 are arbitrary constants... > > And finally present the solution as z(x, t) = ... > > How can I achieve this using only sympy? :P
How would you do it mathematically? Let's take this example as a start: http://en.wikipedia.org/wiki/Method_of_characteristics#Example If I understand it correctly, the solution is given by F(z, x(s), t(s)) = 0. Do you know how to write this equation using sympy? If not, let me research how to do it, I was learning that just last semester, but I forgot already, all I remember is that there is quite a direct way to do that, as long as one can solve the equations. Ondrej --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sympy?hl=en -~----------~----~----~----~------~----~------~--~---
