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-   -   Checking of Collatz problem / conjecture (https://www.mersenneforum.org/showthread.php?t=24661)

pinhodecarlos 2019-08-09 18:55

Go to the computer stats and try to find one available with processed wus. Click on that wu to see its details. For example: [url]https://boinc.thesonntags.com/collatz/result.php?resultid=40998456[/url]

LaurV 2019-08-10 05:00

Down for maintenance :)

pinhodecarlos 2019-08-10 07:20

[CODE]<core_client_version>7.9.3</core_client_version>
<![CDATA[
<stderr_txt>
Collatz Conjecture Sieve 1.40 Linux x86_64 for OpenCL
Written by Slicker (Jon Sonntag) of team SETI.USA
Based on the AMD Brook+ kernels by Gipsel of team Planet 3DNow!
Sieve code and OpenCL optimization provided by Sosiris of team BOINC@Taiwan
kernels_per_reduction=48
threads=7
lut_size=19
sleep=1
reduce_cpu=0
sieve_size=30
Collatz Config Settings:
verbose 1 (yes)
kernels/reduction 48
threads 2^7 (128)
lut_size 19 (4194304 bytes)
sieve_size 2^30 (51085096 bytes)
sleep 1
cache_sieve 1 (yes)
reducecpu 0 (no)
Processor Type NVIDIA
Max Dimensions 3
Max Work Items 1024 1024 64
Max Work Groups 1024
Max Kernel Threads 1024
Device Vendor NVIDIA Corporation
Name TITAN V
Driver Version 418.67
OpenCL Version OpenCL 1.2 CUDA
Device Vendor NVIDIA Corporation
Name TITAN V
Driver Version 418.67
OpenCL Version OpenCL 1.2 CUDA
actual threads 128
6170811732209765980839 - 1179 steps @ 1.40482
6170811732237683321243 - 1334 steps @ 1.40489
6170811732233929053031 - 1528 steps @ 1.40492
6170811732534651731455 - 1608 steps @ 2.80589
6170811732889754196991 - 1727 steps @ 4.4327
6170811734370780556927 - 1833 steps @ 11.2197
6170811734412937127423 - 1851 steps @ 11.4509
6170811774127834587775 - 1970 steps @ 191.823
Start 6170811732191512363008
Stop 6170811784968070496256
Best 6170811774127834587775
Highest steps 1970
Total steps 396855723221023
CPU time 3.80772 seconds
Elapsed time 00:03:56
19:42:25 (25184): called boinc_finish

</stderr_txt>
]]>[/CODE]

dabler 2019-08-19 12:12

To whom it may concern, the situation is now clarified [URL="https://math.stackexchange.com/questions/3314430/how-far-has-collatz-conjecture-been-computationally-verified"]here[/URL].

dabler 2019-08-21 17:17

Computational verification of Collatz problem
 
Would anyone be willing to implement [URL="https://math.stackexchange.com/questions/3330085/computational-verification-of-collatz-problem"]this verification procedure[/URL] effectively (in any programming language) and verify it for higher limits? The underlying operation should nicely fit to [URL="https://en.wikipedia.org/wiki/Bit_Manipulation_Instruction_Sets"]modern instruction sets[/URL] (namely the TZCNT in BMI1 set).

Thanks,

David

Uncwilly 2019-08-21 18:03

[FONT="Arial Black"][COLOR="Blue"][SIZE="2"]MOD Note: Three very small threads about the Collatz problem/conjecture have been merged.[/SIZE][/COLOR][/FONT]

Dylan14 2019-08-21 20:16

1 Attachment(s)
I have written a program in python to implement this procedure: see the attached pdf with the code. I do indeed get the same sequence of n's with this as in the stackexchange post, but the σ's and ε's don't seem to match up. It appears for those in that post you have the values for n+1 (for example, for 27 you have σ = 7, ε = 2 which would yield n = 7*2^2 = 28).

dabler 2019-08-22 12:59

[QUOTE=Dylan14;524198]I have written a program in python to implement this procedure: see the attached pdf with the code. I do indeed get the same sequence of n's with this as in the stackexchange post, but the σ's and ε's don't seem to match up. It appears for those in that post you have the values for n+1 (for example, for 27 you have σ = 7, ε = 2 which would yield n = 7*2^2 = 28).[/QUOTE]

There must be some +- 1 problem. Can you compare your code with [URL="https://github.com/xbarin02/collatz/blob/master/simple2.c#L48"]my own implementation here[/URL]? Basically, a single iteration of the do-while loop is the map taking the input (n,e) pair and computing the output (n,e) pair. I use (n, e) rather than (sigma, epsilon), but the meaning is the same.

Dylan14 2019-08-22 15:16

I checked my implementation with yours and it appears to be the same as mine. I managed to match your sigma and epsilon values in my python code by simply changing

[CODE]decomp(n)[/CODE]to

[CODE]decomp(n+1)[/CODE]so there was a n off by 1 issue in my code. So then my question is why are you keeping track of those values for n+1?


Also, your C code doesn't work in Windows using mingw64 - I get an assertion failed in line 25 of the code, regardless of the input. That is where you do the 3^n bit.

dabler 2019-08-22 17:22

[QUOTE=Dylan14;524278]I checked my implementation with yours and it appears to be the same as mine. I managed to match your sigma and epsilon values in my python code by simply changing

[CODE]decomp(n)[/CODE]to

[CODE]decomp(n+1)[/CODE]so there was a n off by 1 issue in my code. So then my question is why are you keeping track of those values for n+1?

The reason is explained [URL="https://math.stackexchange.com/questions/3311547/alternative-formulation-of-the-collatz-problem?noredirect=1&lq=1"]here[/URL].


Also, your C code doesn't work in Windows using mingw64 - I get an assertion failed in line 25 of the code, regardless of the input. That is where you do the 3^n bit.[/QUOTE]

Probably the [FONT="Courier New"]long[/FONT] type on the platform has only 32 bits in size. On 64-bit Linux systems, the [FONT="Courier New"]long[/FONT] is 64-bit type.

dabler 2019-08-26 13:51

Greetings,

My current single-threaded implementation gives the throughput about 3.99 × 10^9 128-bit numbers per seconds. Any help is welcome!


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