example4_2.m

来自「Matlab 6.X辅助优化计算与设计----源代码」· M 代码 · 共 17 行

%写一个计算目标函数值和Jacobian矩阵的M-file nlsf1.m
function F = nlsf1a(x);
% 计算目标向量的值
n = length(x);
F = zeros(n,1);
i = 2:(n-1);
F(i) = (3-2*x(i)).*x(i)-x(i-1)-2*x(i+1) + 1;
F(n) = (3-2*x(n)).*x(n)-x(n-1) + 1;
F(1) = (3-2*x(1)).*x(1)-2*x(2) + 1;

%调用函数来解此等式
xstart = -ones(1000,1);
fun = @nlsf1a;
load nlsdat1 % Get Jstr
options = optimset('Display','iter',‘JacobPattern',Jstr, 'PrecondBandWidth',1);
[x,fval,exitflag,output] = fsolve(fun,xstart,options);