Thank you Stefan, I will follow your advices. I tried to solve this problem through scikits.bvp_solver (e.x. http://pythonhosted.org/scikits.bvp_solver/examples/examples.example5.html ) cause the second B.C of u' is not initial at x=0 but at x=N(x max). But there I had the same problem, how to make the k working on "function `def my_first_derivative` " example: " return np.array([v, ((k1_func()*k2_func()*(u**(1./3.)))* .. " , what have to write between () ... in books and internet I found many examples, but noone (except relative examples of scikits.bvp_solver) with 2 boundary conditions an coefficients that are arrays...
Please tell me one last think, what you mean "seems you are going in circles with these "k"s" ? I know that k* are functions,but I dont know how to make them work inside another function. How to grap a specific element on each loop ? I know that if I write k1_func(1) call the first element of the array k1. I dont know how to write it inside the function that calculate the derivatives .. thank you for everything Kas . On Sunday, March 31, 2013 10:25:11 AM UTC-6, Stefan Krastanov wrote: > > You should address your questions about scipy and numerics to the > scipy mailing list (the sympy mailing list has a different focus). I > do not understand all of your questions but nonetheless: > > - the interpolated "k"s are just functions. You can call them from > inside the function representing the derivative in the same way that > you would call "sin" or whatever. By the way, it seems you are going > in circles with these "k"s - you have an exact expression that you > evaluate on a grid only to get it interpolated - instead you can just > use the original expression. > > - I do not understand what the Newton method has to do with this (it > is a method for finding zeros of expressions, not solutions to ODEs). > Check the Euler method on wikipedia for the basics of numerical ODEs. > And a note: usually solutions of ODEs are not called "roots" > > A good idea would be to read the introduction tutorials for numpy and > scipy, read some books/articles introducing numerical methods, and > solve some simple equations before you jump to a real world problem. > > And do not forget to read the docs of the libraries that you use. Most > of the questions are already answered there. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
