Re: Fastest way to iterate over a range in steps

< ^ > P N |<>|^_>< --- | ~ ...Help
On 02/06/2010 07:54 PM, Intransition wrote:
> Interesting, I am getting different results:
> 
>   Rehearsal --------------------------------------------------
>   while           12.880000   0.010000  12.890000 ( 13.000285)
>   succ            51.880000   0.000000  51.880000 ( 52.045592)
>   range step      10.760000   3.700000  14.460000 ( 14.518478)
>   step            10.520000   3.740000  14.260000 ( 14.255010)
>   ---------------------------------------- total: 93.490000sec
> 
>                        user     system      total        real
>   while           13.110000   0.000000  13.110000 ( 13.111040)
>   succ            52.650000   0.000000  52.650000 ( 52.654402)
>   range step      10.820000   3.650000  14.470000 ( 14.465861)
>   step            10.380000   3.850000  14.230000 ( 14.233755)
> 
> I had to drop a 0 off LI for my platform. I'm guessing you are running
> 1.9.2? My results are for 1.8.7.

No, 1.9.1:

robert@fussel:~$ allruby xx.rb
ruby 1.8.7 (2009-06-12 patchlevel 174) [i486-linux]
Rehearsal --------------------------------------------------
while           12.920000   0.030000  12.950000 ( 13.175308)
succ            57.090000   0.060000  57.150000 ( 58.147065)
range step       3.690000   0.010000   3.700000 (  3.764357)
step             3.330000   0.000000   3.330000 (  3.414265)
---------------------------------------- total: 77.130000sec

                      user     system      total        real
while           12.900000   0.010000  12.910000 ( 13.136198)
succ            57.170000   0.110000  57.280000 ( 59.248970)
range step       3.680000   0.010000   3.690000 (  4.048842)
step             3.390000   0.000000   3.390000 (  3.837864)
ruby 1.9.1p376 (2009-12-07 revision 26041) [i686-linux]
Rehearsal --------------------------------------------------
while            1.440000   0.000000   1.440000 (  1.586378)
succ             6.140000   0.010000   6.150000 (  6.615136)
range step       2.930000   0.010000   2.940000 (  3.040969)
step             2.810000   0.000000   2.810000 (  2.952599)
---------------------------------------- total: 13.340000sec

                      user     system      total        real
while            1.460000   0.000000   1.460000 (  1.609680)
succ             6.200000   0.000000   6.200000 (  6.464387)
range step       2.960000   0.000000   2.960000 (  3.104242)
step             2.830000   0.000000   2.830000 (  2.962337)
jruby 1.2.0 (ruby 1.8.6 patchlevel 287) (2009-09-04 rev 6586) [i386-java]
Rehearsal --------------------------------------------------
while            5.252000   0.000000   5.252000 (  4.421000)
succ            18.914000   0.000000  18.914000 ( 18.914000)
range step       5.321000   0.000000   5.321000 (  5.321000)
step             5.518000   0.000000   5.518000 (  5.518000)
---------------------------------------- total: 35.005000sec

                      user     system      total        real
while            4.393000   0.000000   4.393000 (  4.393000)
succ            18.992000   0.000000  18.992000 ( 18.992000)
range step       5.695000   0.000000   5.695000 (  5.695000)
step             5.485000   0.000000   5.485000 (  5.485000)
robert@fussel:~$ uname -a
Linux fussel 2.6.31-19-generic #56-Ubuntu SMP Thu Jan 28 01:26:53 UTC 
2010 i686 GNU/Linux
robert@fussel:~$ cat xx.rb

require 'benchmark'

LI = 100_000_000
ST = 5

Benchmark.bmbm 15 do |b|
   b.report "while" do
     i = 0
     while i < LI
       i += ST
     end
   end

   b.report "succ" do
     i = 0
     while i < LI
       i = i.succ
     end
   end

   b.report "range step" do
     (0...LI).step ST do
     end
   end

   b.report "step" do
     0.step LI, ST do
     end
   end
end
robert@fussel:~$

Cheers

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/