[math] PRBS generator

[ferdymercury]

This Pull request:

Changes or fixes:

Adds PRBS generation code

Checklist:

• tested changes locally
• updated the docs (if necessary)

This PR fixes #8199

[phsft-bot]

Can one of the admins verify this patch?

[couet]

LGTM

[hahnjo]

@phsft-bot build

I think new generators should go via ROOT::Math::TRandomEngine, not another TRandomXYZ, right @lmoneta? Also would be good to have some tests.

[phsft-bot]

Starting build on ROOT-debian10-i386/cxx14, ROOT-performance-centos8-multicore/default, ROOT-ubuntu16/nortcxxmod, mac1014/python3, mac11.0/cxx17, windows10/cxx14
How to customize builds

[phsft-bot]

Build failed on windows10/cxx14.
Running on null:C:\build\workspace\root-pullrequests-build
See console output.

Errors:

• [2021-08-18T08:28:49.366Z] CMake Error at C:/build/workspace/root-pullrequests-build/rootspi/jenkins/root-build.cmake:1045 (message):

[phsft-bot]

Build failed on ROOT-debian10-i386/cxx14.
Running on pcepsft10.dyndns.cern.ch:/build/workspace/root-pullrequests-build
See console output.

Errors:

• [2021-08-18T08:37:44.395Z] stderr: error: could not read '.git/rebase-apply/head-name': No such file or directory

[phsft-bot]

Starting build on ROOT-debian10-i386/soversion, ROOT-performance-centos8-multicore/cxx17, ROOT-ubuntu18.04/nortcxxmod, ROOT-ubuntu2004/python3, mac12/noimt, mac11/cxx14, windows10/cxx14
How to customize builds

[dpiparo]

I would like to revive this PR, @ferdymercury do you feel like rebasing so that I can start the builds ?

[hahnjo]

see also #8798 (comment)

[github-actions]

Test Results

    12 files      12 suites   2d 10h 57m 28s ⏱️
 2 628 tests  2 628 ✅ 0 💤 0 ❌
29 840 runs  29 840 ✅ 0 💤 0 ❌

Results for commit 2c3bcff.

[ferdymercury]

@hahnjo Thanks for the comment! I can move it there, but do I really need to derive from TRandomEngine? The parent methods are for double Rndm(), which does not seem very useful to me.
This generator is a binary register generator, so rather a quite different structure, and it is not intended to be used as a normal generator, but rather as a test scenario or helper math functions for electronics testing. It also is inherently templated, etc. It returns an array rather than just a number Rndm(). See https://github.com/root-project/root/pull/8798/files#diff-2e848ceefaff2e24c9b2970fb86a8da1d3d00603fc4f48f920421e603198fab2

Wrt tests, I will 'copy' the mentioned tutorial as 'test' once it's clear where this class should go.

Thanks for the review!! :)

[lmoneta]

Hello @ferdymercury
I am not sure what the use case is for having this generator in ROOT. One could, in principle, also use the bits of the generated numbers of a good generator like RANLUX++.
Do we have users that are asking for this feature?

[ferdymercury]

Hello @ferdymercury I am not sure what the use case is for having this generator in ROOT. One could, in principle, also use the bits of the generated numbers of a good generator like RANLUX++. Do we have users that are asking for this feature?

Thanks for the reply! We discussed this point in the associated issue: #8199 (comment)

[lmoneta]

I still think is very specific, and we could have it maybe as an external addition.

[ferdymercury]

Ok. What do you mean by external? Moving it to just a tutorial? Happy to change that once it's clarified.