Ühel kenal päeval, T, 2009-07-07 kell 00:03, kirjutas Ondrej Certik: > On Mon, Jul 6, 2009 at 1:47 PM, Priit Laes<plaes...@gmail.com> 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.
I got something finally working now Just pull pde-wip branch again... --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sympy?hl=en -~----------~----~----~----~------~----~------~--~---
