Intresting! I have learned much more from this topic than I have in the
last year with J.
On Sun, Apr 5, 2015 at 8:12 PM, David Lambert wrote:
> http://www.jsoftware.com/jwiki/Essays/Odometer
>
> Fastest of these is the sparse solution
> (4 $. $.)@($&1)
>
> To fill your table assuming you've use
Ouch! I'm sorry for incomplete specification, the full one is very very
complex. I wasn't expecting to see a full solution. Ok, I'll try to
simplify specification before starting to solve a problem. Anyway I got the
point and this reply is really helpful, thank you again.
On Sun, Apr 5, 2015 at 5:
http://www.jsoftware.com/jwiki/Essays/Odometer
Fastest of these is the sparse solution
(4 $. $.)@($&1)
To fill your table assuming you've used c notation:
odometer =: (4 $. $.)@($&1)
i=:{.
j=:1&{
k=:{:
($ ([: ((i*j) - (i*k) - (j*k))"1 odometer))2 3 4
0 0 0 0
0 1 2 3
0 2 4
Why do you have recursive functions?
Note that numbers themselves are recursive - most practical
applications that "need recursive functions" can be redefined to
instead "need functions with numeric domains".
Put differently: a specification which specifies *how* something gets
done will often be
I'm not sure. May be I should use memoization instead. I have a bunch of
recursive functions f,g,h,... defined like this:
F(t,i,j,k) is a minimum of
{C(i,j,k)+ sum of all g(t-1, i',j',k) + sum of all h(t-1, i, j", k') }
and
{F(t,i-1,j,k-1)+1},
where C -- user defined cost function,
i' from 0 to i-
Lots of replies already to your main question.
As for
"Another question is how to fill the table with values depending
on indexes of cell? For example, F[i,j,k] = (i * j) - (i * k) + (j * k) ":
As Henry says, you might not in practice need the whole index array;
you also might not need to pop
