MATLAB: Fixed point converter: Ignore code part.

coderfixed-point converterFixed-Point DesignerHDL Coder

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

The C Coder gets through the code fine, but the fixed-point converter does not skip the coder.target('MATLAB') code.

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

Is there any possibility to tell the fixed point converter to skip these lines?

Best Answer

Ignoring a code part in fixed point converter is currenty(R2019b) not supported.

Comment out the section as a temporary fix.

Related Solutions

MATLAB: Coder: Exclude/ignore code sections

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.

MATLAB: Possible bug in Parse function input

This does seem to be a limitation in the implementation of inputParser. Following code show a case where the parser will fail. In this code, the second optional input is a char array.

function a = findArea(width, varargin)
   defaultHeight = 1;
   defaultUnits = 'inches';
   defaultShape = 'rectangle';
   expectedShapes = {'square','rectangle','parallelogram'};
   p = inputParser;
   validScalarPosNum = @(x) isnumeric(x) && isscalar(x) && (x > 0);
   validScalarPosNum2 = @(x) ischar(x); % <---- the optional parameter is char array
   addRequired(p,'width',validScalarPosNum);
   addOptional(p,'height',defaultHeight,validScalarPosNum2);
   addParameter(p,'units',defaultUnits,@isstring);
   addParameter(p,'shape',defaultShape,...
                 @(x) any(validatestring(x,expectedShapes)));
   parse(p,width,varargin{:});
   
   a = p.Results; 
end

now call it like this

>> findArea(7, 'shape', 'square')
Error using findArea (line 14)
No value was given for 'square'. Name-value pair arguments require a name
followed by a value.

I skipped the optional parameter height, but the parser failed to note that.

I guess this is done intentionally by MATLAB to avoid some kind of ambiguity in parsing the inputs. For example, in this case, it is easy to tell since we are using a single optional input. But consider a function that takes several optional inputs and parameters. In that case, it will become difficult for the parser to guess which values are optional inputs and which are parameters.

Note that the parser will only fail if you are taking character array as inputs for optional parameters. I guess the MATLAB expects that the character arrays should be input using parameters.

Best Answer

Related Solutions

MATLAB: Coder: Exclude/ignore code sections

MATLAB: Possible bug in Parse function input

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