[RF] RooFit open issues and backports for 6.28.00 release

[guitargeek]

6.28.00

GitHub issue that we still want to resolve before the v6.28.00 release:

• [RF] Improve precision of binned likelihood fits by redefining normalization term in NLL #11951
  Issue is not closed yet because the solution we have is not perfect, but there is a way of doing it already in v628: with the RooBinIntegrator
• [RF] RooStats tutorial takes forever because of numeric integral #11814
• [RF] RooFit variables fail comparisons in edge cases #11954
• [RF] Problem of memory leak (?) with RooDataSet #8984
  Issue is not closed yet because the solution still needs to be validated to the user, but patch is already merged to master and v628 branch

Other items that still need to be done without any associated GitHub issue:

• New test statistics should consider the Offset() command in RooAbsPdf::fitTo(), @Zeff020
• Write release notes for the change in the KahanSum class, @egpbos
• If you run the testInterface unit test binary in roofitcore, you get errors printed out and there is one disabled test. Please take a look, @Zeff020

Backports that need to be made for the v6.28 branch (in this particular order from top to bottom, to not have a commit history too different from master):

• [math] make KahanSum::operator+= and -= consistent #11940
• [math] remove implicit conversions to/from KahanSum #11941
• [RF][HS3] Add importers and exporters for RooRealSumFunc and RooHistPdf #10210
  Except for the commit to RooStats, which is a fixup only relevant to a commit in master
• [RF] RooPolyFunc improvements #11953
  Excluding the one technical commit about the snapshot() overload
• [RF] Add analytical integral for RooLandau #9539
  Only the first four commits that are not about code modernization
• [relnotes] Add RooFit contrubutors from 6.28 development cycle #11969
• [RF] Avoid code duplication with new private Algorithms.h file #11962
• [RF] Make RooAbsArg::recursiveRedirectServers thread safe #11970
• [RF] Fix and improvements in testSumW2Error #11966
• [RF] Prevent accidental casting from double to int in xroofit #11984
• [RF] Use std::abs all the way in RooFit #11986
• [RF] New RooPlot::createInternalPlotVarClone() function for RooUnitTest #11841
• [RF] Fix copy-paste error in rf205 tutorial and related stressRooFit test #11985
• [RF] Completely implement Offset("bin") feature for fits to RooDataHist #11988
• [RF] More improvements to roofitcore unit tests #11995
• [RF] Make margin in RooAbsRealLValue::inRange() zero by default  #11999
• [RF] Rename stuff in RooMomentMorph(Func)ND to ease spotting difference #12000
• [RF] Explicitly set empty normalization set in RooGenProdProj #12010
• [RF] Fix ranged integrals with factorized variables #12011
• [RF] Make RooFitResult set methods public  #12017
• [RF] Fix problems with dataset generation from a nested RooSimultaneous with proto data #12022
  All commits except for the last one for RooAbsArg, which might be a bit too unsafe...
• [RF] Do not stream RooAbsArg eocache to avoid memory leak when reading back workspaces #12024
• [RF] Add cloneAndOwnDataHist() method to RooHistFunc and RooHistPdf #12029
• [RF] New public accessor methods for various roofit data members #12030
• [RF] Little improvements in RooFit #12033
• [RF] Fix IO and memory problems in RooMomentMorph(Func)ND #12039
• [RF] Don't throw exception if proxies are inconsistent in RooProduct #12046
• [RF] Some performance improvements to RooFit likelihood creation and BatchMode #12051
• [RF] additional public methods for accessing/modifying product factors #12048
• [math] Replace TRef with array indices in TFoamCell #12061
• [RF] RooProduct schema-evolved i/o bug fix #12071
  Only the first commit that is not a fixup to a recent typo is master
• [math] KahanSum release notes for 6.28 #12089
• [RF] New way to fix compute graph with RooAbsArg::compileForNormSet() #12079
• [RF] Improve implementation of RooAbsArg::redirectServers() #12040
• [RF] Extra public accessor methods in root browser classes #12064
• [RF] Increase version number of RooRealVar #12114
• [graf] Additional options for TPad::PlaceBox() method #12066
• [RF] Added offsetting to RooAbsPdf::fitTo #12001
• [RF] Fix signature of RooWorkspace::getSnapshots() #12119
• [RF] New tutorial about bias and numeric issues in binned fits #12056
• [RF] xroofit improvements #12103
• [RF] Fix duplicate ownership problem in RooMomentMorph(Func)ND #12160
• [RF] Final changes to make the ATLAS benchmarks run with BatchMode #12157
• [RF] Implement RooBMixDecay in RooBatchCompute for GPU support #12161
• [RF] Avoid using RooAbsArg::redirectServer() in RooFit #12129

The backports were grouped in a few PRs to v6-28-00-patches:

1. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 1 #11960
2. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 2 #11979
3. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 3 #11993
4. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 4 #12014
5. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 5 #12057
6. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 6 #12083
7. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 7 #12092
8. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 8 #12115
9. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 9 #12120
10. [v628][RF] Backports of RooFit PRs to v6-28-00-patches: Part 10 #12169