HP 38G: Comparison of Factoring Efficiency of SQFO & Pollard's Rho

[Gerald H]

Pollard's Rho algorithm

http://www.hpmuseum.org/forum/thread-3540.html

& Shanks' Square Form algorithm

http://www.hpmuseum.org/forum/thread-3483.html

are two very different approaches to factorization.

For a set of 10 semi-prime numbers having factors varying from 3 to 6 digits the timing on the HP 38G was:

Pol-Rho SQFO

0.1758 0.0775 Mean
0.1965 0.1069 Sample StDev
0.0950 0.0262 Median

in units of 1 hour.

So until a better modulo squaring & GCD programme appears SQFO remains the fastest general factoring programme for the 38G.