secant.m

来自「several numerical method code」· M 代码 · 共 21 行

function secant(func, xr, es)


if nargin<2, error('at least 3 input arguments required'), end
if nargin<3 || isempty(es), es= 0.0001; end
ea = abs(feval(func, xr));
xb = 0;
iter = 0;

while (ea > es)
    xa = xr;
    xr = xa - feval(func, xr)*(xr - xb)/(feval(func, xr) - feval(func, xb));
 iter = iter +1;
    xb = xa;
    ea = abs(feval(func, xr));
    fprintf('%d, %.4f, %.4f\n',iter, xr, ea) % display calculated result
%    if ea <= es, break, end
end