Thread: Prime Gap News
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Old 2020-11-27, 22:54   #200
SethTro's Avatar
Apr 2019

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Originally Posted by henryzz View Post
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

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%).
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