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2023-06-03, 11:45   #1211
henryzz
Just call me Henry

"David"
Sep 2007
Liverpool (GMT/BST)

185816 Posts

Quote:
 Originally Posted by pepi37 srsieve2 ( from last package 2.4.8) If I try to apply factors I got error Fatal Error: Invalid factor: 16*767^504684+1 mod 10994911890479476681 = 8563234858453284832 Fatal Error: Invalid factor: 4*767^500350+1 mod 18446744073709551615 = 2 Factor are confirmed (16*767^504684+1)%10994911890479476681 is Zero (0) (4*767^500350+1)%367677432715278443521 is Zero (0)
I suspect it isn't designed to check factors more than 64 bits large.

2023-06-03, 12:29   #1212
rogue

"Mark"
Apr 2003
Between here and the

3·5·499 Posts

Quote:
 Originally Posted by henryzz I suspect it isn't designed to check factors more than 64 bits large.
That is correct.

 2023-06-05, 11:47 #1213 ryanp     Jun 2012 Boulder, CO 1111110002 Posts FYI, latest SVN build of srsieve2 segfaults on some fairly reasonable looking inputs. Code: $./srsieve2 -s "7*2^n-1" -P 1e13 -n 8e6 -N 20e6 -W 36 -o out.txt srsieve2 v1.7, a program to find factors of k*b^n+c numbers for fixed b and variable k and n Sieving with generic logic for p >= 3 Sieve started: 3 <= p <= 1e13 with 12000001 terms (8000000 <= n <= 20000000, k*2^n-1) (expecting 11559581 factors) Sieving with single sequence c=1 logic for p >= 257 BASE_MULTIPLE = 30, POWER_RESIDUE_LCM = 720, LIMIT_BASE = 720 Split 1 base 2 sequence into 23 base 2^180 sequences. Legendre summary: Approximately 4 bytes needed for Legendre tables 1 total sequences 1 are eligible for Legendre tables 0 are not eligible for Legendre tables 0 have Legendre tables in memory 1 cannot have Legendre tables in memory 0 have Legendre tables loaded from files 0 required building of the Legendre tables 518400 bytes used for congruent q and ladder indices 259200 bytes used for congruent qs and ladders Segmentation fault 2023-06-05, 12:04 #1214 rogue "Mark" Apr 2003 Between here and the 1D3D16 Posts Quote:  Originally Posted by ryanp FYI, latest SVN build of srsieve2 segfaults on some fairly reasonable looking inputs. Code: $ ./srsieve2 -s "7*2^n-1" -P 1e13 -n 8e6 -N 20e6 -W 36 -o out.txt srsieve2 v1.7, a program to find factors of k*b^n+c numbers for fixed b and variable k and n Sieving with generic logic for p >= 3 Sieve started: 3 <= p <= 1e13 with 12000001 terms (8000000 <= n <= 20000000, k*2^n-1) (expecting 11559581 factors) Sieving with single sequence c=1 logic for p >= 257 BASE_MULTIPLE = 30, POWER_RESIDUE_LCM = 720, LIMIT_BASE = 720 Split 1 base 2 sequence into 23 base 2^180 sequences. Legendre summary: Approximately 4 bytes needed for Legendre tables 1 total sequences 1 are eligible for Legendre tables 0 are not eligible for Legendre tables 0 have Legendre tables in memory 1 cannot have Legendre tables in memory 0 have Legendre tables loaded from files 0 required building of the Legendre tables 518400 bytes used for congruent q and ladder indices 259200 bytes used for congruent qs and ladders Segmentation fault
Thanks for the bug report. I will take a look.

 2023-06-05, 14:30 #1215 rogue     "Mark" Apr 2003 Between here and the 1D3D16 Posts I found a bug when it generated Legendre tables for single sequences. I fixed that and pushed the code change. But I ran into another issue. I have a work-around, but I suspect another bug that I need to dig into.
 2023-06-07, 13:39 #1216 rogue     "Mark" Apr 2003 Between here and the 3×5×499 Posts mtsieve 2.4.9 is released. Here are the changes: Code: framework: Added command line switch -6. When the removal rate is computed as "seconds per factor", this is the number of minutes to includes in that rate. It can exceed that number of minutes, but only if no factors are found. fnbcsieve: version 1.7.1 For base 2 do not adjust mink or maxk when they are even. End user can use -r to remove those terms. srsieve2/srsieve2cl: version 1.7.1 Fix two issues with generating Legendre tables that can cause program to crash. Fix issue where some sequences are removed due to incorrect algebraic factorizations. I also added on FUTURE item: Code: Add feature to compute rate for the last xx factors instead of seconds per factor. With the two changes I have not been able to reproduce the srsieve2 crash. It should fix the single sequence and multi-sequence Legendre table creation issues.
 2023-06-10, 19:08 #1217 ryanp     Jun 2012 Boulder, CO 23×32×7 Posts I'm also seeing xyyxsievecl hang on inputs like this: Code: $./xyyxsievecl -s "-" -x 3 -X 16 -y 1e6 -Y 1200e3 -g 16 -G 16 -P 1e8 -o xyyx_minus.txt xyyxsieve v2.0, a program to find factors numbers of the form x^y+y^x or x^y-y^x Quick elimination of terms info (in order of check): 0 because x >= y 1400007 because the term is even 265357 because x and y have a common divisor At this point, it seems to just be stuck. I've left it open for hours and it's not apparently doing anything. This is on a machine with an NVIDIA A100... 2023-06-10, 21:54 #1218 pepi37 Dec 2011 After 1.58M nines:) 110111100102 Posts I do some more experiment with srsieve2cl to find fastest way for sieving single sequence. Regardless fact it is "simple fact" i will ask to confirm Quote:  GPU primes per worker is 85411840 Sieve started: 10000680668335321 < p < 15e15 with 8480 terms (2250390 <= n <= 2999886, k*53^n+1) (expecting 92 factors) p=10002326398611403, 10.08M p/sec, no factors found, 0.0% done. Will more primes per worker result as faster sieving speed?  2023-06-15, 12:54 #1219 Happy5214 "Alexander" Nov 2008 The Alamo City 100000001002 Posts All of the non-OpenCL executable directives in the Makefile include$(LD_FLAGS_OPENCL), which fails on computers without OpenCL.
2023-06-15, 14:16   #1220
rogue

"Mark"
Apr 2003
Between here and the

3·5·499 Posts

Quote:
 Originally Posted by Happy5214 All of the non-OpenCL executable directives in the Makefile include $(LD_FLAGS_OPENCL), which fails on computers without OpenCL. Did you use "make cpu_all" or just "make"? Use "make cpu_all" if you have no OpenCL. 2023-06-16, 20:53 #1221 Happy5214 "Alexander" Nov 2008 The Alamo City 22×257 Posts Quote:  Originally Posted by rogue Did you use "make cpu_all" or just "make"? Use "make cpu_all" if you have no OpenCL. I only needed one program, so I used "make srsieve2". It compiled, but failed to link (specifically mentioning -lOpenCL). Line 386 of the Makefile (the rule for srsieve2) is: Code: $(CC) $(CPP_FLAGS)$(OPT_CPP_FLAGS) $(LD_FLAGS_OPENCL) -o$@ $^$(LD_FLAGS)

Last fiddled with by Happy5214 on 2023-06-16 at 20:57

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