Coder: Exclude/ignore code sections?

I'm using coder to generate C source code. Of course many matlab functions are not available for coder. But I still want to use these functions when running the code in matlab.

Currently I have to comment out all these sections that are not coder-friendly when doing C source code generation. Is there something I can wrap them in to make the coder ignore them?

[Sean de Wolski]

Alex, please contact technical support and let them know what functions you would like code generation support for.

Answer 1

[Mike Hosea]

You can wrap them with

if coder.target('MATLAB')
...
end

Or if that gives an error,

if isempty(coder.target)
...
end

You can also declare unsupported functions as "extrinsic" and use them in generated mex files. This practice has some pitfalls, and where unsupported data structures are involved, it can rather involved and advanced. However, in the simpler cases it is very simple. If foobar() is MATLAB function that you are passing, say, an m-by-n matrix to, and foobar returns, say, a 1-by-n vector (for example, this is what SUM would do with an m-by-n matrix where neither m nor n is 1), you would write:

coder.extrinsic('foobar');
y = zeros(1,size(x,2));
y = foobar(x);

Or, if you don't want to mess with coder.extrinsic:

y = zeros(1,size(x,2));
y = feval('foobar',x);

The y = zeros(...) line looks like wasted effort, but what it really does is tell the compiler what to expect by the next line, so it can copy the data from the MATLAB return into local storage. Basically, if you know what a function will return given the type of the input, then you just initialize the output variable to the appropriate type and then call the function.

[Alex]

Great info Mike, thanks. Works like a charm, and got me to understand this coder a bit more.

[Jan Siegmund]

This is a great feature but somehow it does not work.

I am using the HDL Coder and escape an Inputparser with

if coder.target('MATLAB')
    p = inputParser;
    %...Inputparser Stuff
    addOptional(p, 'variable', 'default', @(x)ischar(x));
    %...Inputparser Stuff
else
    %if nargin = ...
end

However the coder still complains about the anonymus function ischar() in that input parser section.

'@(x)ischar(x)' is an anonymous function. Anonymous functions are not supported for fixed-point conversion.

It seems, that the coder gets through the first stages fine, but complains later on. I want the coder to ignore

all of the code in coder.target('MATLAB').

[Jan Siegmund]

Follow up question

[Steven Lord]

You don't need an anonymous function to do this:

@(x)ischar(x)

Just specify a regular old function handle to the ischar function.

@ischar

[Jan Siegmund]

Thanks @Steven,

I also had the fixed-point designer struggle with a "load(...)" function which was clearly escaped by "coder.target('MATLAB')". Using "coder.load(...)" will help here I guess?

[Jan Siegmund]

Converting to a function handle is possible, but how about combined logic, like

@(x) ~isempty(x) && ~isvector(x)

?

[Jan Siegmund]

Update: and even function handles are not supported:

'@ischar' function handles are not supported for fixed-point conversion.