- ## Compute divided difference of `f` at points `xs`. The argument `xs`
- ## is assumed to be a vector containing at least one element. If it
- ## contains n elements, the (n-1)st divided difference will be
- ## calculated.
- order = length(xs);
-
- if (order < 1)
- ## Can't do anything here. Return nothing.
- dd = NA;
- elseif (order == 1)
- ## Our base case.
- dd = f(xs(1))
- else
- ## Order > 1, recurse.
+ % Compute divided difference of `f` at points `xs`. The argument `xs`
+ % is assumed to be a vector containing at least one element. If it
+ % contains n elements, the (n-1)st divided difference will be
+ % calculated.
+ %
+ % INPUTS:
+ %
+ % * ``f`` - The function whose divided differences we want.
+ %
+ % * ``xs`` - A vector containing x-coordinates. The length of `xs`
+ % determines the order of the divided difference.
+ %
+ %
+ % OUTPUTS:
+ %
+ % * ``dd`` - The divided difference f[xs(1), xs(2),...]
+ %