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mex-file creation

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dario cecchetti
dario cecchetti 2017-11-13
关闭： MATLAB Answer Bot 2021-8-20
I was trying to create a mex-file, however I can't do it beacuse Matlab shows the following error: Class function_handle is not support by coder Type. I wrote the following script and functions to calculate the solution of non-linear equation.
clear
clc
ep=10^(-6); % tollerance
itermax=50; % number max of iterations
a=0; % a,b initial interval
b=2;
[x,iter] = Bisection(@f,a,b,ep,itermax)
%%%functions
function [x,iter] = Bisection(f,a,b,ep,itermax)
%
% Function for the solution of the non-linear equation
% f(x)=0
% by the BISECTION method
%
% INPUT data:
% f name of the MATLAB function implementing
% the non-linear function
%
% a,b initial interval [a,b]
% such that f(a)f(b) < 0
%
% ep tolerance (>0)
%
% OUTPUT data:
% x solution of the non-linear equation
% iter number of performed iterations
%
fa = feval(f,a);
fb = feval(f,b);
if fa*fb > 0
fprintf('\n\nThe initial interval does not satisfy f(a)f(b) < 0.')
return
end
iter=0;
% while abs(a-b) > ep+eps*max(abs(a),abs(b))
while abs(a-b) >= 2*ep && (iter < itermax)
mid = (a+b)/2;
fmid = feval(f,mid);
if fa*fmid<=0
% root in [a,mid].
b = mid;
fb = fmid;
else
% root in [mid,b].
a = mid;
fa = fmid;
end
iter=iter+1;
end
x = (a+b)/2;
function [ y ] = f( x )
y=x.^2-1;
end
  1 个评论
Jan
Jan 2017-11-13
You forgot to mention, when the error occurs. Do I understand correctly, that the shown code works reliable in Matlab and it fails only, if you try to compile it? Then please explain, if compiling is really needed.

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回答（1 个）

Jan
Jan 2017-11-13
编辑：Jan 2017-11-13
  3 个评论
显示 1更早的评论
Jan
Jan 2017-11-13
Did you read my answer?
dario cecchetti
dario cecchetti 2017-11-13
of course, I answered at your following answer "You forgot to mention, when the error occurs. Do I understand correctly, that the shown code works reliable in Matlab and it fails only, if you try to compile it? Then please explain, if compiling is really needed." Then I checked your second answer and I couldn't to solve it. I'm sorry but my english it's not very good.

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