You have several options:
1. Use empty matrices as you have done. Advantages: Optional arguments can be anywhere. Disadvantages: You still have to pass empty matrices for optional arguments.
function T = Tavg(a,b,c,d)
if isempty(a)
a = defaulta;
end
%same for b,c,d
usage:
T = Tavg(a, [], c, []);
2. Use nargin as per James example. Advantages: dead simple. Disadvantages: Only the last(s) argument(s) is(are) optional. You can't have an optional argument in the middle
3. Use the property/value pair that mathworks use for a number of functions like plot. Advantages: Very flexible. Disadvantages: you have to do all the parsing and the user has to refer to the documentation to know the names of the properties.
function T = Tavg(varargin)
a = defaulta; b = defaultb; ...
for opt = 1:3:nargin
switch varargin{opt}
case 'a'
a = varargin{opt+1};
case 'b'
b = varargin{opt+1};
...
usage:
T = Tavg('a', a, 'c', c);
4. Use a class for your function and class property for the optional arguments (like a functor, if you're familiar with C++). Advantages: Very flexible. Automatic tab completion for arguments. Self-documented. Can be reused without having to reenter the arguments. Disadvantages: usage may be too unusual for some people as it's OOP.
classdef Tavg
properties
a = defaulta;
b = defaultb;
...
end
methods
function T = Apply(this)
T = this.a + this.b - this.c * this.d;
end
end
end
usage:
TAvgfun = Tavg;
TAvgfun.a = a;
Tavgfun.c = c;
T = Tavgfun.Apply(); % or T = Apply(TAvgfun);
