GMP-ECM Assertion

[yoyo]

Hello,
after a run of more than 2h on a 269 digit value ecm crashes:

ecm -v -nn -timestamp -chkpnt checkpnt -inp in 110000000
ecm: mul_fft.c:2534: mpn_mul_fft_full_a: Assertion `cc == 0' failed.

It was on this host

What does it mean?
yoyo

[bdodson]

Originally Posted by yoyo

What does it mean?
yoyo

Perhaps you've hit a quota on Top10 factors below p50?
-bd

[akruppa]

Uh-oh, failed assertion in the Schönhage-Strassen code... that sounds like a real bug. What exactly was the input number? Did you use a 32 or 64 bit binary? Can I get the particular binary that produced this failed assertion?

Alex

[yoyo]

The client crashed on these 2 values:
b1=43000000 value=1334841693486483854297291433137878966023389106988070173618883095349142276658801443685194636723178104744943017304654073916334484066159032897675225956934301532395866525183256725820587
b1=110000000 value=77728012992649681652257138568390176857212890117660654903605188181803793527234365966882492843633887478337495016140443699327828796305552459390410906211419468091843928832883028959106125700776135225351872298944331308559262827186539091839208835236997045999057406305939986879

But this value runs without problems:
b1=43000000 value=6893391342692867777051495012539640454628902784450454655293804913060414424159750295978281554900778090687802025606849968951990208020026932694644119483338508192513688560991912493381

A 64 bit version of ecm was used, which was compiled on a 64 bit Ubuntu system in a VM with:
* ./configure CFLAGS="-static" --enable-fat --with-gmp=/usr/
* make
* make checks

yoyo

[Andi47]

Originally Posted by yoyo

The client crashed on these 2 values:

b1=43000000 value=1334841693486483854297291433137878966023389106988070173618883095349142276658801443685194636723178104744943017304654073916334484066159032897675225956934301532395866525183256725820587
b1=110000000 value=77728012992649681652257138568390176857212890117660654903605188181803793527234365966882492843633887478337495016140443699327828796305552459390410906211419468091843928832883028959106125700776135225351872298944331308559262827186539091839208835236997045999057406305939986879

Do you still have the logfile? Which sigma did the crashed ECM-curve use?

[yoyo]

No, I do not have the logfile. But I'll contact the user who runs the curve to rerun it.
yoyo

[yoyo]

Ok, the user did the run again and it aborted:

$ ./ecm-6.2.1-4_i686-pc-linux-gnu -v -nn -timestamp -chkpnt checkpnt -inp in 43000000 > out
ecm-6.2.1-4_i686-pc-linux-gnu: mul_fft.c:2534: mpn_mul_fft_full_a: Assertion `cc == 0' failed.
Aborted

out:

$ cat out
GMP-ECM 6.2.1 [powered by GMP 4.2.2] [ECM]
Running on ubuntu-wcg
Input number is 1334841693486483854297291433137878966023389106988070173618883095349142276658801443685194636723178104744943017304654073916334484066159032897675225956934301532395866525183256725820587 (181 digits)
[Sun Jan 11 14:52:24 2009]
Using MODMULN
Using B1=43000000, B2=240490660426, polynomial Dickson(12), sigma=3049191634
dF=65536, k=5, d=690690, d2=17, i0=46
Expected number of curves to find a factor of n digits:
20 25 30 35 40 45 50 55 60 65
2 5 14 55 246 1277 7553 49797 358989 2841353
Step 1 took 1553860ms
Using 42 small primes for NTT
Estimated memory usage: 371M
Initializing tables of differences for F took 400ms
Computing roots of F took 21650ms
Building F from its roots took 31660ms
Computing 1/F took 51440ms
Initializing table of differences for G took 580ms
Computing roots of G took 17660ms

I was wrong, it is a 32 bit Ubuntu system.

yoyo

[bdodson]

Originally Posted by bdodson

Perhaps you've hit a quota on Top10 factors below p50?
-bd

I take it back (if I may). Four p5x's, including the largest p56. Does
this mean ecm is now a running boinc project? -Bruce

[yoyo]

Originally Posted by bdodson

I take it back (if I may). Four p5x's, including the largest p56. Does
this mean ecm is now a running boinc project? -Bruce

Yes, I send ecm work units via my Boincserver. It is currently under test, but runs quite smoothly. Some things I still have to do in the next weeks/month.
yoyo

PS: If somebody wants to help and implement things, you are welcome. I wuold need:
- programmer/compiler for Mac
- implementation of ecmnet protocol / change of ecmclient