Avoid load filename.mat in every function-file called from a main-script-file

I'm quite new to Matlab, so Im still unused to some terminology.

Now I have many functions, and every function is within their own matlab-file. The functions I call from a main script-file where i call the functions, disp their results and more.

In many of the functions I use

load datafile.mat,

loading the same datafile (that contains matrices and vectors) in many functions. Now Im looking for a way to avoid loading the datafile so many times, and just do it for all functions in just a bit of code. Maybe this is to be done from within the scripting-file? How exactly can this be done.

Also there are some lines of code I consistently use in several functions, is there a way to just have these lines of code in one place? Here is an example of the code I reuse:

[pX sX] = size(X);

Also another thing I'd like is to avoid having to call a function from within another function if that's possible? Cause some functions are "reused" several times in different functions?

Answer 1

[Jan]

You can load the data file once and provide the values by using it as input arguments of the called functions:

function YourMainFunction
Data = load('datafile.mat');   % Never LOAD without catching the output
YourFunc1(Data);
YourFunc2(Data);
...

It is the best way to create tiny values like in [pX sX] = size(X) locally. It takes just some micro-seconds, but when you debug the code or modify it, you need at least minutes to get the overview.

There is no problem with re-using functions. So please explain why you want to avoid this. Usually it is the goal of each professional programmer to re-use as many code as possible, because this reduces the time for programming and debugging.

[Olga Sirley]

Thank you that is a relief having that clarified up a bit!

Ok so if I understand this correctly, I add that bit of code you provided into my main-"file" where I call all the functions (which in my situation are all stored in separate files in the same folder as the main-"file").

So I when call a function from within my main-"file", I've told the function from within my main-"file" that the function im calling from the external file to use data that is loaded from the datafile.mat, or in shorter words I simply use the following code in my main-"file" which tells my main-"file" to pass Data onto MyFunctionName1 which returns back externalFunction1 to my main-"file" ready for use?

Data = load('datafile.mat');   
externalFunction1 = MyFunctionName1(X, Data);

disp ( externalFunction1 );

[Jan]

This looks fine. You would exactly the same when you run this:

x = 0.2;
y = sin(x)