Matlab Coder: Avoiding that input variables are converted to constants

When generating C-code for this function, the resulting tinyplot.cpp creates the same output regardless of the input to the function. It somehow assumes that the calling function at code generation time will be the only function to ever call it. How do I force the input variables of tinyplot to remain input variables, so that it's generated plot depends on what inputs are used when calling tinyplot.cpp?

function tinyplot(dataVector,PlotWidth, PlotHeight)
% A vector of input data, 'dataVector', is plotted in the command window
% using dots. The plot size is scaled into 'PlotWidth' columns and
% 'PlotHeight' rows.
if nargin == 1
    PlotWidth = 10;
    PlotHeight = 10;
end
coder.inline('never');
overSizedFactor = length(dataVector)/PlotWidth;
dataMax = ceil(max(dataVector));
dataMin = floor(min(dataVector));
if dataMax>dataMin
    dataVector_scaled = (dataVector-dataMin)/(dataMax-dataMin)*PlotHeight;
else
    dataVector_scaled=dataVector;
end

bgMarker = ' ';
plotMarker = '.';

fprintf(1,repmat('_',1,PlotWidth));
for y=1:PlotHeight
    fprintf(1,'\n');

      for x=1:PlotWidth
          combineWhichVectorCells = uint32(1+floor((x-1)*overSizedFactor)):...
                                    uint32(  floor((x-0)*overSizedFactor));
          value = mean(dataVector_scaled(combineWhichVectorCells));
          if value >= PlotHeight-y
              if value < PlotHeight-y+1
                  fprintf(1,plotMarker);
              else
                  fprintf(1,bgMarker);
              end
          else
              fprintf(1,bgMarker);
          end

      end
  end
  fprintf(1,['\n',repmat('_',1,PlotWidth),'\n']);

if ~coder.target('MATLAB')
    coder.ceval('std::cin.get');
end

end

Answer 1

[Ryan Livingston]

I assume that you are generating code for another function which calls tinyplot. Please correct me if I am wrong. If you would like to be able to call tinyplot in your generated code you could use it as the entry-point function like:

codegen tinyplot -args {1:10,1,1} -report

Alternatively, in the function that calls tinyplot are the arguments all constants such as:

function foo()
tinyplot(1:10,10,10);

If so you could pass in the top-level input arguments:

function foo(a,b,c)
tinyplot(a,b,c);

codegen foo -args {1:10,1,1}

Since a,b,c are all arguments to the entry-point function, the call to tinyplot will not include constants for the arguments.

If neither of those resolve it for you, it would be helpful to know how you are generating code for tinyplot and related functions. What does your codegen command look like or how has your Coder project been set up?