Here was my simplistic factoring one-liner, and its results on the first digits from pi (1-11).
Code:
perl -Mstrict -Mwarnings -le 'my $n = shift or die qq{Requires 1 numbe +r argument.}; my $o = $n; my @f = (); my $i = 2; while ( $n % $i == 0 + ) { push @f, $i; $n /= $i; } $i++; while ( $n >= $i ) { while ( $n % + $i == 0 ) { push @f, $i; $n /= $i; } if ( $n > $i ) { $i += 2; } } p +rint $o, q{ = }, join q{*}, @f;'
Output:
$ for number in 3 31 314 3142 31416 314159 3141593 31415927 314159265 +3141592654 31415926536 ; do time -p perl -Mstrict -Mwarnings -le 'my +$n = shift or die qq{Requires 1 number argument.}; my $o = $n; my @f += (); my $i = 2; while ( $n % $i == 0 ) { push @f, $i; $n /= $i; } $i +++; while ( $n >= $i ) { while ( $n % $i == 0 ) { push @f, $i; $n /= +$i; } if ( $n > $i ) { $i += 2; } } print $o, q{ = }, join q{*}, @f;' + $number ; done 3 = 3 real 0.05 user 0.00 sys 0.04 31 = 31 real 0.04 user 0.00 sys 0.03 314 = 2*157 real 0.03 user 0.00 sys 0.03 3142 = 2*1571 real 0.03 user 0.01 sys 0.01 31416 = 2*2*2*3*7*11*17 real 0.03 user 0.00 sys 0.03 314159 = 314159 real 0.07 user 0.04 sys 0.04 3141593 = 7*13*19*23*79 real 0.03 user 0.00 sys 0.01 31415927 = 31*103*9839 real 0.03 user 0.01 sys 0.01 314159265 = 3*3*5*7*127*7853 real 0.03 user 0.03 sys 0.01 3141592654 = 2*139*2131*5303 real 0.03 user 0.00 sys 0.01 31415926536 = 2*2*2*3*3*436332313 real 47.17 user 47.03 sys 0.03
Enjoy.
In reply to Re: How not to do prime factorization
by atcroft
in thread How not to do prime factorization
by thisisdada
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