> Will change the "engine" to keep going to 2^33 after finding the > first factor & report the results from that. OK, here's the results. (All factors to 2^33 found, input is 159,975 largest primes < 36 million) Sieve 6 smallest primes, 3517525 calls, 40.15s Sieve 10 smallest primes, 2972446 calls, 39.82s Sieve 14 smallest primes, 2693566 calls, 41.75s Sieve 18 smallest primes, 2515556 calls, 44.76s (The first 2 primes are sieved out "mod 120" as in George's code. The others are done in groups of 4 since you can do arithmetic modulo p in an 8 bit field if p<128) Model the time as T=aX + bY + Z where X is time per call to the factoring routine, Y is time to sieve 1 extra prime and Z is a fixed overhead. So we have 2693566X + 14Y + Z = 41.75 2972446X + 10Y + Z = 39.82 3517525X + 6Y + Z = 40.15 Solving this system of equations (to a sensible precision) yields (X = 8.49E-6,Y = 1.074,Z = 3.84) The result for 18 primes sieved is consistent with this model to within a couple of tenths of a second. The timings come from the PC RTC, which has a resulution of 55 mS, so this fit is reasonable. Will, am sending you an extra message containing the "factors found" file for verification. Regards Brian Beesley ________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
