Mersenne: Re: Bug in version 22.10

[EWMAYER]

Brian Beesley wrote:

>>>
{system 1}
[Wed Oct 30 21:00:54 2002]
UID: beejaybee/slug1, M8589491 completed P-1, B1=40000, B2=420000, WY2:
DE3C48D7
...
[Tue Nov  5 10:15:49 2002]
P-1 found a factor in stage #1, B1=40000.
UID: beejaybee/slug1, M8589491 has a factor: 42333443925749970809

{system 2}
[Thu Oct 31 23:12:50 2002]
UID: beejaybee/caterpillar, M8564431 completed P-1, B1=45000, B2=618750, WY2:
DDB16BFB
[...]
[Tue Nov  5 12:44:02 2002]
P-1 found a factor in stage #2, B1=45000, B2=618750.
UID: beejaybee/caterpillar, M8564431 has a factor: 9592239270614293063
<<<

The first of these is slightly larger than 2^65, so it was likely
cheaper to find via p-1 than via sieving. But the second is only
a tad larger than 2^63, i.e. under the hardware long int length,
and thus sieving to 2^64 should have been quite fast. George - is
it faster to do p-1 for numbers this size than to sieve to 2^64?

-Ernst