Beefy Boxes and Bandwidth Generously Provided by pair Networks
Keep It Simple, Stupid

Re: RE: sieve of Eratosthenes

by cforde (Monk)
on May 19, 2001 at 04:23 UTC ( #81667=note: print w/replies, xml ) Need Help??

in reply to RE: sieve of Eratosthenes
in thread sieve of erothenes

In the pursuit of efficiency I have come up with a slightly different implementation: Carl1. In Carl2 I tried to optimize at the expense of a few more characters.

On my WinNT PIII 800Mhz machine with ActiveState 522 both of these are faster than ase's Bit Vector implementation.

Carl1: @p=(1);for(2..10000){if(!$n[$_]){push@p,$_;for($k=$_*$_;$k<=10000; +$n[$k]=1,$k+=$_){}}} Carl2: @p=(1,2);for($_=3;$_<=10000;$_+=2){if(!$n[$_]){push@p,$_;for($k=$_ +*$_;$k<=10000;$n[$k]=1,$k+=$_){}}}
One thing that I found interesting is that for n less than about 10,000, Carl1 is significantly faster than Carl2. The loop control overhead must be pretty significant.

Have fun,
Carl Forde

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://81667]
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others perusing the Monastery: (13)
As of 2018-10-23 14:26 GMT
Find Nodes?
    Voting Booth?
    When I need money for a bigger acquisition, I usually ...

    Results (125 votes). Check out past polls.