Hi Dan,
I liked your recent blog post.
Two typos:
- in the stack based definition of split-reduce, the final * should be call
- some combinators are missing inline declarations
Continuing our IRC discussion, here is the fastest version of
split-reduce I could come up with:
: split-reduce ( seq start quot -- value )
pick length {
{ 0 [ drop nip ] }
{ 1 [ 2drop first ] }
{ 2 [ >r drop first2 r> call ] }
{ 3 [ >r drop first3 r> 2apply ] }
[ drop >r >r halves r> r> [ [ split-reduce ] 2curry 2apply ]
keep call ]
} case ; inline
It's several times faster than a linear reduce for computing the
factorial of 40,000.
I've put this into sequences and changed sum and product to use it.
Slava
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