how to write functions in an m-file?

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learner
learner on 16 Jul 2015
Answered: Image Analyst on 16 Jul 2015
If I define a function like
function (cost) = objective (time)
cost = some non linear equation in time
It shows error in line-1 input argument that is at '(time)'. Please help me how to write a function?
Also, if my function depends on two variables say t1 and t2, how to define it? I've tried using
function (cost) = objective (t1 t2)
and also tried this:
time = [t1 t2]
function (cost) = objective (time)
But it shows error.
  3 Comments
learner
learner on 16 Jul 2015
Edited: Walter Roberson on 16 Jul 2015
Thanks GopalKrishnan, but it's typo in my question. earlier I've tried
function [ f ] = fun1(x)
x=[2 3 4]
And it worked fine for me but in other file, I've written:
function [ cost ] = objective( time )
time=[t1 T]
Also I tried
function [ cost ] = objective( t1 T )
Or
function [ cost ] = objective( t )
t=[t1 T]
But every time it showed an error. I am unable to identify, what went wrong.
Please help.
Walter Roberson
Walter Roberson on 16 Jul 2015
Please copy the entire text of the error message.

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Answers (3)

chef13
chef13 on 16 Jul 2015
You should write something like that:
function [ cost ] = objective( time )
%UNTITLED Summary of this function goes here
% Detailed explanation goes here
% Here you put what your function does
end
I hope it helps you.

Ellison Castro
Ellison Castro on 16 Jul 2015
I think it should be constructed like this:
function[output1, output2, ...] = function_name(input1, input2, ...)
% Insert your main code here using your inputs and returning outputs.
end;
You should also remove this line of code if you're using it at the beginning.
clear; clc; clf;
The first line of the m-file must be the function syntax. To call the function, create another m-file using this syntax:
[variable1, variable2, ...] = function_name(value1, value2, ...)
Your number of inputs should be equal to your specified inputs on your function's m-file.
  1 Comment
chef13
chef13 on 16 Jul 2015
Edited: chef13 on 16 Jul 2015
Don't put the semicolomn after the end , it is not needed.

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Image Analyst
Image Analyst on 16 Jul 2015
time is a built-in function. Use another name for it, like myTimes.

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