MATLAB: Optional Function input arguments

functionfunctionsinputMATLABmatlab function

I am writing a function and basically it does a set of command on the inputted matrices, How can i specify that the user can enter any number of matrices as inputs and the code will perform the command on all of them. So if three matrices are inputted then the code runs for the 3 and if 20 are inputted the commands are done for all 20. I hope i explained my problem well enough

Best Answer

You would use varargin,

https://www.mathworks.com/help/matlab/ref/varargin.html#f77-385387

function theFunction(varargin)
  for i=1:numel(varargin)
      
      matrix=varargin{i};
      
      ...
  end
end

Related Solutions

MATLAB: Check if a number of varibles in a function satifies a condition.

There are already tools for performing these tasks. Check out the InputParser class [ ref, ref ]. It will allow you to declare three sets of arguments: required, optional, and param/value pairs. For each parameter, you will be able to define a check function, as well as a default value for all but required parameters.

EDIT: just as an example, here is the beginning of a function using an input parser

 function [hFig, hAxis, hLegend, hPatches] = bar_varWidth( colWidth, ...
    data, varargin )
    % --- 1. Parse input parameters.
    parser = inputParser ;
    parser.StructExpand  = true ;
    parser.CaseSensitive = false ;
    parser.addRequired( 'colWidth', @isnumeric ) ;
    parser.addRequired( 'data', @isnumeric ) ;
    parser.addParamValue( 'legend', [], @(x) ischar(x) || iscell(x)  ) ;
    parser.addParamValue( 'xTickLabel', [], @(x) isnumeric(x) || iscell(x)  ) ;
    parser.addParamValue( 'xTickLabelFormat', '%.2f', @ischar ) ;
    parser.addParamValue( 'xTickLabelShiftThreshold', 10, @isnumeric ) ;
    parser.addParamValue( 'xTickLabelAngle', 90, @isnumeric ) ;
    parser.addParamValue( 'xTickLabelLineLength', [], @isnumeric ) ;
    parser.parse( colWidth, data, varargin{:} ) ;
    args = parser.Results ;
    % --- 2. ...

and here all parameters are accessible as fields of args, e.g.

    args.colWidth
    args.legend

MATLAB: Two optional parameters mutually exclusive

Thales - you could just pass a structure as the second input to your function, and depending upon which field has been defined, use that to determine what code gets executed (length vs step)

 function y = f(x,params)
 if isfield(params,'opt1')
     v = linspace(a,b,params.opt1);
 elseif isfield(params,'opt2')
     v = a:params.opt2:b;
 end
 % etc.

The function could be called then as

 y=f(42, struct('opt1',102));
 y=f(42, struct('opt2',102));

The structure could be defined before you call the function, or as above.

Best Answer

Related Solutions

MATLAB: Check if a number of varibles in a function satifies a condition.

MATLAB: Two optional parameters mutually exclusive

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