2006-01-15, 10:23 #18 Kosmaj     Nov 2003 2×1,811 Posts R. Gerbicz I noticed a large slow-down of dodeca.exe ver. 1.0 on a large range. Have a look. Case 1: Code:  n=70, kmin=15, kmax=3000000000000000, version=1.0 Using the first 10 primes to reduce the size of the sieve array Time=1968 sec. Case 2: Code: n=70, kmin=3000000000000000, kmax=10000000000000000, version=1.0 Using the first 11 primes to reduce the size of the sieve array Status: 0.3 percentage of the project is complete. Time thusfar: 69 sec. I stopped the second instance but 0.3% in 69 sec means 23000 sec for the range 7000T wide, while less than 2000sec were needed for a range 3000T wide. The only difference is the number of primes used (10 -> 11) so I guess it's related to magic_constant now set to 32000. Can you have a look and tell us how to avoid this kind of problems. Can you possibly set magic_constant dynamically based on input parameters (kmin and kmax) or enable "-x" on the cmd-line as you mentioned before for octo.exe. Thanks. BTW, I checked all n=67-70 to 3000T but found no new DodecaProths. Last fiddled with by Kosmaj on 2006-01-15 at 10:26