Thread: Prime Gap News View Single Post
2020-11-27, 22:54   #200
SethTro

"Seth"
Apr 2019

24×17 Posts

Quote:
 Originally Posted by henryzz Have just submitted 177 new gaps of which 23 are new gap lengths(assuming I counted correctly). This might take a while for the queue to clear. How deep does Danaj's surround_primes function sieve for gaps of length 150000? Also is there a way of determining what % of time is spent sieving vs prp testing by this function? I am wondering where the cross-over point is for switching to testing using pfgw.
I believe surround_primes uses

Code:
def sieve_depth_pg(log2n):
log2log2n = int(math.ceil(math.log2(log2n)))
return log2n * (log2n >> 5) * int(log2log2n * 1.5) >> 1
I've personally found the cross-over point for pfgw to be around ~8000 bits but I haven't profiled the overhead from Danaj's script.

I believe % time in sieve is very small (0.1% - 1%).