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-   -   some tools for weights computing... (https://www.mersenneforum.org/showthread.php?t=7213)

Thomas11 2015-07-03 11:02

[QUOTE=pepi37;405180]I search for this article and will say this
"old" nash for 93*10^n-1 gives -93 10 5030 5045
"new" nash gives "only" -93 3116 3123
So what is correct ?

Second: how to calculate nash weight from 1 to 1000 on base 3?
mnash calculate only base 2, right?

Thanks for answer[/QUOTE]

It seems that you mixed up those values:

The old Nash tool as given here in this thread was specifically created for k*2^n-1 and will yield:
[CODE]nash 93 --> 93 3116 3123[/CODE]
But this is the Nash weight for the sequence 93*2^n-1

The new (universal) Nash tool (originally created upon your request) and given in [URL="http://www.mersenneforum.org/showpost.php?p=358591&postcount=13"]another thread[/URL] yields the correct answer:
[CODE]nash -93 10 --> -93 5030 5045[/CODE]
This is the Nash weight for the sequence 93*10^n-1

BTW.: Note the sign change between the two versions: For the new one enter negative k for the Riesel side, e.g. -k*b^n+1 for k*^b^n-1.

Regarding your second question:
mnash is restricted to base 2. But one could easily write a little Python or Perl script which does the looping over k and calls the new Nash tool...

Thomas11 2015-07-03 12:17

1 Attachment(s)
[QUOTE=Thomas11;405221]mnash is restricted to base 2.[/QUOTE]

I prepared a new version of mnash which is now also capable for bases other than b=2.
For convenience the attached ZIP file also contains the latest single k universal base nash.exe.

A positive k means k*b^n+1, negative k means k*b^n-1 (e.g. entering as -k*b^n+1)

Usage examples are given below:

Nash weights for sequences k*3^n-1 (for even k=10-20):
[CODE]mnash -20 -10 2 3 (= kmin kmax kstep base)

-20 3 2960 2960
-18 3 2686 2667
-16 3 1430 1435
-14 3 1524 1523
-12 3 2359 2369
-10 3 4054 4038[/CODE]
Note the reversed order due to the negative k values. If base is omitted, b=2 is assumed.

and for k*7^n+1:
[CODE]mnash 10 20 2 7

10 7 4000 3979
12 7 2407 2411
14 7 0 0
16 7 3211 3210
18 7 2392 2387
20 7 0 0[/CODE]

Nash weight for the single sequence 14*17^n-1:
[CODE]nash -14 17

-14 17 803 800[/CODE]
Same here: If base is omitted, b=2 is assumed.

pepi37 2015-07-03 13:51

Mnash rules!
Thanks so much!

Thomas11 2015-07-06 08:15

1 Attachment(s)
I did some minor improvements to the "mnash" tool:

(1) The earlier version was restricted to k<2^31, the new one can handle k of arbitrary size.

(2) The values "kmin" and "kmax" now have the meaning of start and stop values and you're no longer restricted to (numerically) increasing order.

(3) The sign of the step size doesn't matter. It will be adjusted properly. So a step size of 2 may be entered as "2" oder "-2".

(4) If only kmin and kmax are given, a step size of 2 is assumed. And base=2, of course.


To give an example:
[CODE]mnash -2 -10 2 13

-2 13 3721 3713
-4 13 0 0
-6 13 1416 1414
-8 13 963 965
-10 13 0 0
[/CODE]

And for some very large Ks:
[CODE]mnash 123456789012345678901234567890 123456789012345678901234567880 2 7

123456789012345678901234567890 7 3543 3571
123456789012345678901234567888 7 1370 1345
123456789012345678901234567886 7 0 0
123456789012345678901234567884 7 2876 2886
123456789012345678901234567882 7 2171 2148
123456789012345678901234567880 7 0 0
[/CODE]

pepi37 2015-12-24 23:53

Can you make modification of this tool adding just one number

1 100 2 2 [COLOR=Red][B]10

[/B][COLOR=Black]Last number means: print only K that have weight 10 or less.[/COLOR]
[/COLOR]

Thomas11 2015-12-25 09:55

[QUOTE=pepi37;420122]Can you make modification of this tool adding just one number

1 100 2 2 [COLOR=Red][B]10

[/B][COLOR=Black]Last number means: print only K that have weight 10 or less.[/COLOR]
[/COLOR][/QUOTE]

I will add this feature when I'm back from Christmas vacations (don't have a real computer with me)...

pepi37 2015-12-27 22:04

Multi5 is still way faster then mnash.
So also can you just change behavior of last number

32000000025 KMIN 32001000000 KMAX 30 KSTEP 600 minimum weight for printing
Since if we use this tool we look at very small weight of number do that last number print only K less then not above then ( as it now)
With that output will be drastically smaller .
Thanks

Thomas11 2016-01-04 12:43

1 Attachment(s)
[QUOTE=pepi37;420122]Can you make modification of this tool adding just one number

1 100 2 2 [COLOR=Red][B]10

[/B][COLOR=Black]Last number means: print only K that have weight 10 or less.[/COLOR]
[/COLOR][/QUOTE]

Here comes the new version of MNash with the print filtering feature added.

Usage example:
[CODE]MNash.exe -1 -100 2 2 800[/CODE]

The additional parameter (800) controls the printing, e.g. the result line will only be printed if at least one of the two weights is less or equal to the limiting parameter. The output of the above example is thus:
[CODE] -11 2 795 791
-29 2 495 485
-37 2 630 629
-43 2 633 640
-59 2 639 642
-71 2 593 604
-73 2 800 818
[/CODE]

If looking for high weight sequences just enter the limit with a negative sign, e.g.:
[CODE]MNash.exe -1 -100 2 2 -3000[/CODE]

This will print only lines with weight >= 3000:
[CODE] -45 2 3747 3767
-69 2 3438 3437
-75 2 3181 3184
[/CODE]


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