Re: optimizing the miller-rabin algorithm

I'm not sure I can help with your question. But you do say you are doing this in part to learn Perl, so I'll make a few (kindly meant) comments about your code.

First, always add use strict; use warnings; to your code. They will save you much grief and tearing of hair

Avoid C style for loops. For example replace

for (my $n=91001; $n<93000; $n++)

with:

for my $n (91001..93000)

Do not use $a and $b as general purpose variables. They are magical and are used in the context of sort.

DWIM is Perl's answer to Gödel

Comment on Re: optimizing the miller-rabin algorithm Select or Download Code

Replies are listed 'Best First'.
Re^2: optimizing the miller-rabin algorithm by punklrokk (Scribe) on May 16, 2006 at 01:57 UTC
If I use your version of a For Loop, how do I tell it to iterate two steps instead of one? JP Bourget (punklrokk) MS Information and Security Rochester Institute of Technology Rochester, NY	[reply]
Re^3: optimizing the miller-rabin algorithm by GrandFather (Saint) on May 16, 2006 at 02:09 UTC
Either use the C style for loop in that case or, if appropriate, do something like `for ($start/2..$end/2)` with $start and $end both even (but that's rather clunky!). The Perl style for is very good for iterating over lists so you can do something like `for (1.5, 2..4, @moreNumbers)`. Generally you should think Perl style for first, then C style if you really need it. DWIM is Perl's answer to Gödel	[reply] [d/l] [select]
Re^3: optimizing the miller-rabin algorithm by ikegami (Patriarch) on May 16, 2006 at 17:07 UTC
You could do `for (0..(5-1)/2) { # 1..5, step 2 my $i = $_*2 + 1; ... }` [download] but you're probably better off falling back to a C-style loop in that case. As an aside, the above trick is particularly useful when dealing with floats. `>perl -le "for (my $i=0; $i<10; $i+=0.1) { print $i }" ... 8.79999999999998 8.89999999999998 8.99999999999998 9.09999999999998 9.19999999999998 9.29999999999998 9.39999999999998 9.49999999999998 9.59999999999998 9.69999999999998 9.79999999999998 9.89999999999998 9.99999999999998 >perl -le "for (0..99) { my $i = $_ / 10; print $i }" ... 8.8 8.9 9 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9` [download]	[reply] [d/l] [select]


Welcome to the Monastery
	PerlMonks