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Old 2021-02-07, 00:24   #2
Feb 2018

23 Posts
Default With more Ram and a better machine

compared to a better machine it is no match.

Windows10 64bits 16Gb Ram cpu I5-3470
steps of 1,000,000,000,000,000

This is done under 17 minutes and would have taken 277 hours on the other pc.

GMP-ECM 7.0.5-dev [configured with GMP 6.1.2, --enable-asm-redc] [P-1]
Resuming P-1 residue saved by jocelyn@jocelyn-Dell-DV051 with GMP-ECM 7.0.4 on Fri Feb 5 22:54:18 2021
Input number is ((2^1571-1))/1250961804686347854556649368571289367 (437 digits)
Using special division for factor of 2^1571-1
Using lmax = 16777216 with NTT which takes about 9792MB of memory
Using B1=10000000000-10000000000, B2=999999913515224-2206728710203396, polynomial x^1
P = 64579515, l = 16777216, s_1 = 7434240, k = s_2 = 3, m_1 = 7742389
Can't compute success probabilities for B1 <> B2min
Step 1 took 0ms
Computing F from factored S_1 took 199391ms
Computing h took 24828ms
Computing DCT-I of h took 52891ms
Multi-point evaluation 1 of 3:
Computing g_i took 97109ms
Computing g*h took 106985ms
Computing gcd of coefficients and N took 37187ms
Multi-point evaluation 2 of 3:
Computing g_i took 97891ms
Computing g*h took 107078ms
Computing gcd of coefficients and N took 37312ms
Multi-point evaluation 3 of 3:
Computing g_i took 97454ms
Computing g*h took 106343ms
Computing gcd of coefficients and N took 36453ms
Step 2 took 1002672ms
Peak memory usage: 9684MB

Now we just have to wait and see if it leads to a factor.
It always depends on B1 being high enough.
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