Hi Jose, I'm not interested in systems of differential equations, but in systems of "ordinary" non-linear equations. An example is to determine the zeros of the gradient of the following function in the variables x_1, x_2, x_3, x_4, x_5 and x_6:
4800000000*sqrt((((600*(4000.0/x_6 + 0.00599872/x_3)/((10.0/x_6 + 2/x_5 + (1.49968e-05)/x_3)*x_5) + 6000.0/x_5 + 0.00899808/x_2)/(((4000.0/x_6 + 0.00599872/x_3)/((10.0/x_6 + 2/x_5 + (1.49968e-05)/x_3)*x_5) + 3/x_4 + 10.0/x_5 + (1.49968e-05)/x_2)*x_4) + 10.0/x_4 + (1.49968e-05)/x_1 + 50)/((600*(4000.0/x_6 + 0.00599872/x_3)/((10.0/x_6 + 2/x_5 + (1.49968e-05)/x_3)*x_5) + 6000.0/x_5 + 0.00899808/x_2)/(((4000.0/x_6 + 0.00599872/x_3)/((10.0/x_6 + 2/x_5 + (1.49968e-05)/x_3)*x_5) + 3/x_4 + 10.0/x_5 + (1.49968e-05)/x_2)*x_4) + 10.0/x_4 + (1.49968e-05)/x_1) + 1)^(-2))*sqrt((10.0/x_6 + 2/x_5 + (1.49968e-05)/x_3)^(-2))*sqrt(((600*(4000.0/x_6 + 0.00599872/x_3)/((10.0/x_6 + 2/x_5 + (1.49968e-05)/x_3)*x_5) + 6000.0/x_5 + 0.00899808/x_2)/(((4000.0/x_6 + 0.00599872/x_3)/((10.0/x_6 + 2x_5 + (1.49968e-05)/x_3)*x_5) + 3/x_4 + 10.0/x_5 + (1.49968e-05)/x_2)*x_4) + 10.0/x_4 + (1.49968e-05)/x_1)^(-2))*sqrt(((4000.0/x_6 + 0.00599872/x_3)/((10.0/x_6 + 2/x_5 + (1.49968e-05)/x_3)*x_5) + 3/x_4 + 10.0/x_5 + (1.49968e-05)/x_2)^(-2))*sqrt(x_4^(-2))*sqrt(x_5^(-2)) I guess that fsolve, find_root or newton_krylov may work,as Andrzej suggested, but I didn't understand the syntax until now. Urs Hackstein 2011/11/3 Jose Guzman <[email protected]> > ** > On 31/10/11 16:01, Urs Hackstein wrote: > > Hi all, > > maybe it is a silly question, but I wonder whether there is a routine > in sage to find a numerical solution of a system of nonlinear > (in)equalities which can not be computed directly. > > Thanks a lot in advance. > > Urs Hackstein > > > It would be very helpful if you simply show us a small example. I was > trying to solve a system of non-linear differential equations and found an > example in the sage reference ( > http://www.sagemath.org/doc/reference/sage/calculus/desolvers.html). Not > sure if this is what you need. > > Jose > > -- > 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/sage-support > URL: http://www.sagemath.org > -- 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/sage-support URL: http://www.sagemath.org
