Octave can solve sets of nonlinear equations of the form
using the function fsolve
, which is based on the MINPACK
subroutine hybrd
.
For example, to solve the set of equations
you first need to write a function to compute the value of the given function. For example:
function y = f (x) y(1) = -2*x(1)^2 + 3*x(1)*x(2) + 4*sin(x(2)) - 6; y(2) = 3*x(1)^2 - 2*x(1)*x(2)^2 + 3*cos(x(1)) + 4; endfunction
Then, call fsolve
with a specified initial condition to find the
roots of the system of equations. For example, given the function
f
defined above,
[x, info] = fsolve ("f", [1; 2])
results in the solution
x = 0.57983 2.54621 info = 1
A value of info = 1
indicates that the solution has converged.
The function perror
may be used to print English messages
corresponding to the numeric error codes. For example,
perror ("fsolve", 1)
prints
solution converged to requested tolerance
Tolerances and other options for fsolve
may be specified using the
function fsolve_options
.