OpenEuphoria

Re: Slice sequence--new algorithm

• Posted by jbabor at PARADISE.NET.NZ Feb 21, 2001
• 422 views

Nice one, Derek! Redundant copying bothered me a bit, but obviously
not enough to do anything about it :). jiri


----- Original Message -----
From: <ddparnell at bigpond.com>
To: "EUforum" <EUforum at topica.com>
Sent: Thursday, February 22, 2001 2:02 AM
Subject: Re: Slice sequence--new algorithm


> Its nearly always hard to improve on any of Jiri's routines, but I
might
> have a slight speed improvement for this one.
>
> I noticed that Jiri's method does a lot of work for no effect until
the
> first occurrance of 'n' in 's'. So I tested for that condition first
and
> then applied Jiri's method. This gave me about a 30% average speed
increase
> using the test program below.
>
> --------remove.e------------------
> global function remove(sequence s, object n)
>     integer p
>
>     -- Is there any 'n' in 's'?
>     p = find(n , s)
>     -- If not, then get out of here.
>     if p = 0 then
>         return s
>     end if
>
>     -- Start the sequential search and shift
>     -- from the first 'n'
>     for i = p+1 to length(s) do
>         if compare(s[i], n) then
>             s[p] = s[i]
>             p += 1
>         end if
>     end for
>     return  s[1..p-1]
> end function
>
>
> ---------testrem.ex---------------------
> include remove.e
>
> atom e
> sequence VOID
> integer x
>
> -- Reset the counter
> x = 0
>
> -- Calculate the stop time (10 seconds from now)
> e = time() + 10
>
> -- Until the time's up, do the tests and count them.
> while e > time() do
>     x += 1
>
>     VOID = remove({2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,1}, 1)
>     VOID = remove({1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,1}, 1)
>     VOID = remove({}, 1)
>     VOID = remove({1}, 1)
>     VOID = remove({1,1}, 1)
>     VOID =
> 1)
>     VOID = remove({2,3,4,5,6,7,8,9,0,1,1,1,1,2,3,4,5,6,7,8,9,0}, 1)
>     VOID =
> 1)
>     VOID =
>
},"the
> ")
>     VOID =
>
}, 1)
>
> end while
> -- Display how many cycles I got through in 10 seconds.
> ? x
>
> --------------
> On my machine I'm getting an average of 17,000 test cycles per
second and
> 12,800 per second using Jiri's routine.
>
> ------
> Derek Parnell