what is the meaning ???

if nargin < 5, s_verbose = 'on'; end
if nargin < 4, s_interactive = 'off'; end
if nargin < 3, lastEig = size(vectors, 1); end
if nargin < 2, firstEig = 1; end

Answer 1

[James Tursa]

You don't show the entire code, but my guess would be this is inside a function that looks something like this:

function outputs = myfunction(vectors,firstEig,lastEig,s_interactive,s_verbose)
if nargin < 5, s_verbose = 'on'; end
if nargin < 4, s_interactive = 'off'; end
if nargin < 3, lastEig = size(vectors, 1); end
if nargin < 2, firstEig = 1; end
    :
   etc

nargin is a function that returns the actual number of arguments passed into a function. So the code in question is simply assigning default values for those arguments that were not actually passed in. E.g., if the caller only passed in four arguments and did not pass in that last s_verbose argument, then the above code would assign the value 'on' to the s_verbose local variable.

[ghida hayajneh]

why i use this nargin if i dont need it in my code and not passed in E.G