Hi Thomas, On Thu, Jun 27, 2013 at 8:32 PM, Thomas Moore <tommo...@live.com.au> wrote: > I'm contemplating using sympy in a program which will need to symbolically > solve a set of simultaneous and possibly non-linear equations. However, it's > obviously not possible to find symbolic solutions in many cases, but if > sym.solve can't find an explicit solution what I'd really like is for some > way of delivering a simplified set of simultaneous equations. > > Let me give an example which gives me some hope: > > eq1 = x + y - sym.log(x) - 3 > eq2 = x**2 + z**2 - 4 > eq3 = x + y - 15*z - 100 > > sym.solve((eq1, eq2, eq3), (x,y,z)) > > Obviously this is going to be tough to solve completely, and Sympy does > fail, but the error I recieve is: > > NotImplementedError: could not solve 15*z - log(sqrt((-z + 2)*(z + 2))) > + 97 > > And it looks like, under the hood, Sympy has in fact almost completely > simplified the equations. We have an equation in terms of z alone, and > (hopefully) we could have a second equation in terms of x and z and then a > third equation in terms of all three variables. > > I'm just wondering if there is some function within sympy to simplify sets > of simultaneous equations by eliminating variables.
I don't know how to do that, apart from manually substituting one equation into the other. Do you know the structure of your equations? How do you generate them, where do they come from? Maybe it is possible to design an algorithm that can do what you want. Ondrej -- 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. For more options, visit https://groups.google.com/groups/opt_out.
