20200520, 20:03  #1 
Mar 2019
5·13 Posts 
GMPECM with gwnum failure
Got this failure today. I cannot tell if this is a bug in GMPECM or GWNUM, or some combination?
Code:
$ echo "(7^2048+1)/4119427741479153633869060968771666377359362"  ./ecm v c 100 11e7 GMPECM 7.0.4 [configured with GMP 6.2.0, GWNUM 29.8, enableasmredc] [ECM] Tuned for x86_64/k8/params.h Due to incompatible licenses, this binary file must not be distributed. Input number is (7^2048+1)/4119427741479153633869060968771666377359362 (1689 digits) Found number: 1*7^2048 + 1 Using mpz_mod Using B1=110000000, B2=900514153782, polynomial Dickson(30), sigma=0:16110665023593047747 dF=199680, k=2, d=2081310, d2=13, i0=40 Expected number of curves to find a factor of n digits: 35 40 45 50 55 60 65 70 75 80 34 133 600 3065 17462 108584 733594 5340128 4.2e+07 3.5e+08 Using gwnum_ecmStage1(1, 7, 2048, 1, 110000000, 1) ecm: Fgw.c:399: gw_ecm_stage1: Assertion `siz_x <= (unsigned long) ((gw_x)>_mp_alloc)' failed. Aborted 
20200520, 20:43  #2 
P90 years forever!
Aug 2002
Yeehaw, FL
6,833 Posts 
I believe the bug is in Fgw.c
The lines: Code:
mpz_init2 (gw_x, (gw_n+1)*gw_log_2(gw_b)+64); mpz_init2 (gw_z, (gw_n+1)*gw_log_2(gw_b)+64); This is an overkill solution: Code:
mpz_init2 (gw_x, (gw_n+1)*(gw_log_2(gw_b)+1)+64); mpz_init2 (gw_z, (gw_n+1)*(gw_log_2(gw_b)+1)+64); 
20200520, 22:37  #3  
Mar 2019
1000001_{2} Posts 
Quote:
The fix does seem to be working locally. I don't know if the GMPECM developers monitor this forum; perhaps they should be made aware of the proposed fix? 

20200521, 09:49  #4 
P90 years forever!
Aug 2002
Yeehaw, FL
6,833 Posts 
The developers report the problem is fixed in revision 3084

Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
GWNUM  enzocreti  enzocreti  22  20190314 18:35 
LLR V3.8.2 using gwnum 26.2 is available!  Jean PennĂ©  Software  25  20101101 15:18 
GWNUM?  Unregistered  Information & Answers  3  20100912 19:52 
GWNUM as DLL?  Cyclamen Persicum  Software  1  20070102 20:53 
compiling gwnum  ATH  GMPECM  8  20060717 18:02 