How to define input types in Matlab Coder for a function that has a varying number of input?

I have a function let's say sq_dist(). This function can be called like this sq_dist(a,b) or sq_dist(a). This function includes slow operations and thus I am trying to make a Mex version of it hoping that it will run faster. I am using the Matlab Coder GUI to do so. In order to define input types (in the define input screen) i use a function that calls sq_dist(a,b) and sq_dist(a) to automatically determine input. This gives me an error: Error determining type for input sq_dist:b. Index exceeds matrix dimensions. Here is my function:

 n = 50; 
 dim = 50; 
 a = rand(n, dim);  
 b = rand(n, dim); 

 u = sq_dist(a, b); 
 v = sq_dist(a);

So, since sq_dist can be called in different ways I am not sure how to define its input in the Coder.

If i manually set the input to double :inf x :inf for a and b the mex file is compiled but i get a runtime error: Function 'sq_dist' called with wrong number of arguments: expected 2, received 1.

Answer 1

[srj4anoop]

Hi Alex,

You can make use of 'varargin' keyword to pass variable number of arguments to a function. For more info on varargin refer the following link

http://www.mathworks.com/help/matlab/ref/varargin.html

Also, refer to the following link on the rules to follow while using 'varargin' for code generation

http://www.mathworks.com/help/simulink/ug/rules-for-using-variable-length-argument-lists-for-code-generation.html

[Alex]

It is still not very clear how to use varargin given the code I have given above in the context of Matlab Coder, specifically after reading the limitations from the link you suggested.