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Old 2021-06-20, 01:57   #1
birtwistlecaleb
 
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Question Why is my computer going slower?

Before i did the PRP for M111388003, I had speeds of around 12-15 ms per iteration, now, i have speeds of ~20 ms per iteration. Is it just that PRP iterations require more time that LL iterations? (Left=LL Double check Right=PRP S2)
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Last fiddled with by birtwistlecaleb on 2021-06-20 at 02:07 Reason: Not accurate
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Old 2021-06-20, 02:22   #2
axn
 
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LL & PRP have similar speed.

Small exponent and large exponent do not
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Old 2021-06-20, 02:23   #3
Uncwilly
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Look ate size of the exponent that you are working on. 64,xxx,xxx vs 111,xxx,xxx
111M is a much larger exponent and will require a larger FFT. Not all iterations are equal in required compute. If you were doing an exponent down around 11M It would go faster. The time per iteration between PRP and LL is comparable.
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Old 2021-06-20, 02:23   #4
birtwistlecaleb
 
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Thanks!

Last fiddled with by birtwistlecaleb on 2021-06-20 at 02:24
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Old 2021-06-20, 03:11   #5
MattcAnderson
 
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Welcome to MersenneForum.org birtwistlecaleb !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
glad to have you participating
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Old 2021-06-20, 14:52   #6
kriesel
 
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For fixed hardware performance, primality test time ~ c p2.1 where p is the exponent; iteration time is then ~c p1.1. Larger exponents require larger fft lengths which take longer to compute. Read up on some background at https://www.mersenneforum.org/showthread.php?t=24588
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