I tried to develop a code in MATLAB to solve 3 nonlinear equations using newton raphson method, but it seems that the code is not working, does anyone have the ability to fix it:
function [root,ea1,ea2,ea3,iter]=newtraph(xr,yr,zr,func,jac,es,maxit)
% Define f(x)
func(xr,yr,zr) = [(xr^2)+(2*xr*yr*zr)+(3*yr^2); (xr*yr)+(yr*zr); (yr*xr^2)+(8*zr)];
% Define Jacobian matrix
jac(xr,yr,zr) = [2*xr+2*yr*zr 2*xr*zr+6*yr 2*xr*yr; yr xr+zr yr; 2*yr*xr xr^2 8];
if nargin
Hi, you should better use the "fsolve" function available under MATLAB to solve your set of equations. Best
Hi again, "fsolve" can be used to find the numerical solution of a set of equations F(x) = 0 (see the help of fsolve).
Actually, I wanted to make my own program, not to use 'fsolve' command !! Thank you for sharing thoughts.
Create a function file with the equations (residual) e.g getF, afterwards, create another function file containing the Jacobian e.g getJ. you can then solve the nonlinear using the following algorithm.
for i=1: itermax
F=getF( x......)
J=getJ(x......)
Dx=-J\F
x=x+Dx
F=getF(x.....)
if norm (F)< tol
break
end
end
were tol is the tolerance e.g 10^-6 and 'itermax' is the maximum number of iterations, which you define before running the code. In addition, you need an initial guess e.g x0=[x1 x2 x3]. If you still don't get it, provide the equation and i can help with the code.
- Badges
- Science topic