Re prime95 / mprime at least, assuming enough disk space is available, overall-compute-optimal (proof & server & cert total effort) proof powers are thought to be, based on information provided by George Woltman, for some version v30.x of mprime/prime95, perhaps v30.3:
Quote:
Originally Posted by Prime95
1.7M - 6.7M = 7
6.7M - 26.6M = 8
26.6M - 106.5M = 9
106.5M - 414.2M = 10
414.2M+ = 11
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and
Quote:
Originally Posted by Prime95
...it looks like the next transition will be near 1600M.
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So power 10 is the best choice for first test wavefront through 100Mdigit and somewhat higher.
And
Quote:
Originally Posted by kriesel
Looks like about every 2 bits on fft length is +1 on proof power. So (extrapolating in Mlucas fft lengths) that would imply power 12 would be sufficient to ~6.2G, ~1.87 Gdigit, not something of concern for decades or centuries.
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(See table at end of Mlucas source code file get_fft_radices.c)
Extrapolating higher, power 13 would cover optimal up to 414.2/106.5 * 6.2 G ~ 24. G, well past the maximum fft length 512 Mi of Mlucas v20.x which will support up to ~8.9 G exponent.
And extrapolating as needed to go lower, than prime95's commonb.c source code provides (power 5):
420K - 1.7M power 6
105K - 420K power 5
~26K - 105K power 4
~6.5K - 26K power 3
~1.6K - 6.5K power 2
~400 - 1.6K power 1
The crossover exponent values are somewhat dependent on program efficiency, so somewhat subject to change among mprime/prime95 versions, and across applications (gpuowl; eventually Mlucas).
Recent attempts to re-derive the proof power transition points for mprime/prime95 from program runs, source code examination, and cost function analysis have not duplicated the above, giving different results instead.
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