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-   -   mfaktc bug? (https://www.mersenneforum.org/showthread.php?t=24342)

Prime95 2019-04-25 22:34

mfaktc bug?
 
This was submitted by a reliable user:

no factor for M384000053 from 2^76 to 2^77 [mfaktc 0.21 barrett76_mul32_gs]

Note that mfaktc used a barrett76 kernel to TF to 2^77. Bug?

srow7 2019-04-25 23:13

I got barrett87_mul32_gs
using mfaktc 0.21
CUDA driver 9.10
eta 1hr

kriesel 2019-04-26 01:21

[QUOTE=Prime95;514734]This was submitted by a reliable user:

no factor for M384000053 from 2^76 to 2^77 [mfaktc 0.21 barrett76_mul32_gs]

Note that mfaktc used a barrett76 kernel to TF to 2^77. Bug?[/QUOTE]
Failed to replicate here, with GTX 1080 Ti, mfaktc v0.21 CUDA 8. I tried to tempt it with
Factor=384000053,7[B]5[/B],77.

[CODE]Apr 25 19:47 | 4612 99.9% | 1.562 0m02s | 1148.18 90677 n.a.%
Apr 25 19:47 | 4615 100.0% | 1.571 0m00s | 1141.60 90677 n.a.%
no factor for M384000053 from 2^75 to 2^76 [mfaktc 0.21 barrett[B]76[/B]_mul32_gs]
tf(): total time spent: 25m 4.678s

Starting trial factoring M384000053 from 2^76 to 2^77 (39.85 GHz-days)
k_min = 98382621478680
k_max = 196765242961865
Using GPU kernel "barrett[B]87[/B]_mul32_gs"
Date Time | class Pct | time ETA | GHz-d/day Sieve Wait
Apr 25 19:47 | 0 0.1% | 3.196 51m05s | 1122.31 90677 n.a.%
Apr 25 19:47 | 3 0.2% | 3.398 54m15s | 1055.60 90677 n.a.%[/CODE]Is it possible it's a copy/paste error?
[CODE]UID: Kriesel/condorette-gtx1070, no factor for M153500033 from 2^77 to 2^78 [B][mfaktc 0.21 barrett87_mul32_gs]
UID: Kriesel/condorette-gtx1070, no factor for M149447533 from 2^73 to 2^74[/B] [mfaktc 0.21 barrett76_mul32_gs]
[/CODE] becomes [CODE]UID: Kriesel/condorette-gtx1070, no factor for M153500033 from 2^77 to 2^78 [mfaktc 0.21 barrett76_mul32_gs]
[/CODE]via an accidental deletion of the [B]bold[/B] text.

Madpoo 2019-04-26 03:28

[QUOTE=kriesel;514746]...Is it possible it's a copy/paste error?...[/QUOTE]

I don't know. It seems unlikely, and the user kept trying to submit the results over and over (because the server was correctly rejecting the impossible result).

Tried submitting it 4 times I think, and the last attempt had a mix of other TF results. The others were TF to 72 - 75 bits with the same "mfaktc 0.21 barrett76_mul32_gs" client string, but that one result to 77 bits from the 76-bit client ... that's definitely strange.

Like George said, it's a user that we wouldn't expect to try anything fishy, thus wondering if it's some strange bug in the client that mysteriously allowed it.

dcheuk 2019-04-26 03:58

[CODE]got assignment: exp=384000053 bit_min=76 bit_max=77 (39.85 GHz-days)
Starting trial factoring M384000053 from 2^76 to 2^77 (39.85 GHz-days)
k_min = 98382621478680
k_max = 196765242961865
Using GPU kernel "barrett87_mul32_gs"
Date Time | class Pct | time ETA | GHz-d/day Sieve Wait
Apr 25 22:55 | 0 0.1% | 1.504 24m02s | 2384.92 82485 n.a.%
Apr 25 22:55 | 3 0.2% | 1.548 24m43s | 2317.13 82485 n.a.%
Apr 25 22:55 | 7 0.3% | 1.455 23m12s | 2465.23 82485 n.a.%[/CODE]

Like Kriesel said, probably a copy and paste error. :davieddy:

Just read Madpoo's comment. Maybe the user submitted it with lots of other ones but found the server rejected that specific one? Then tried to submit it like 4 more times?
Maybe ask the user directly to see if the result.txt is still intact?

LaurV 2019-04-26 05:45

Can't replicate it here either.

Was an IP address check done? As it is not difficult to send results in the name of other user (we did it in the past, for "credit trade"), maybe someone is trying to discredit somebody else?
Or contact the user and ask?


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