Enhancing a Function so that it can be called using the following syntax

HELP. I want to be able to call the below function using the following syntax

    working_program
    working_program(n)
    working_program(n,m)
    working_program(n,'method')
    working_program(m,n,'method')

If a user inputs no values a single random number should be generated If a user inputs (n), the function should return a n x n square matrix If a user inputs (m,n), the function should return a m x n matrix* * * *

    function y = working_program(n, method)
    switch method
        case 'NR' %parameters from Numerical Recipes book
            a=1664525;
            b=1013904223;
            c=2^32;
        case 'RANDU' %RANDU generator
            a=65539;
            b=0;
            c=2^31;
        otherwise
            error('Invalid method')
    end
    seed=mod(a*etime(clock,[1993 6 30 8 15 0])+b,c);
    y= zeros(n,1);
    y(1)= seed;
    for i=2:n
        y(i)=mod(a*y(i-1)+b,c);
    end
    y=y/c; %normalizing so all values are between 0 and 1

Answer 1

[Guillaume]

You use nargin to check how many arguments were passed and ischar or isnumeric to test whether they're strings or numeric, e.g: (there are many ways to do this, you could also use varargin)

y = function working_program(n, arg1, method)
  switch nargin
    case 0
      n=1; m=1; method = 'RANDU';
    case 1
      m=n; method = 'RANDU';
    case 2
      if ischar(arg1)
        m=n; method = arg1;
      else
        m=arg1; method = 'RANDU';
      end
    case 3
      m=arg1;
   end
   %the rest of your code
end

[Jessica Benidict]

That code works perfectly if I have no input value for working_program however what about the other cases? I want a 3 by 4 matrix of random number to occur if i type in working_program(3,4) instead I am given

if true
  working_program(3,4)

ans =

    0.4125
    0.4122
    0.7758
  end

[Guillaume]

I just showed you how to write a function that accept a variable numbers of input of different types. I assumed that the rest of your program would behave properly given the values n and m, e.g:

%the rest of the program
%... do wathever you want with method
y = rand(n, m); %generate a n x m matrix of random numbers