use hash table for speed in HcalCalibrationsSet classes

[kpedro88]

It turns out that running std::find() and push_back() on a vector n times is an O(n²) operation, and when you have 700,000 cells*, it takes about an hour. This is suboptimal.

Since these classes are CalibFormats, not CondFormats, and therefore not serialized, there is no reason not to use a hash table.

attn: @bsunanda, @lgray

*in the fine-segmented BH case for HGCal

[cmsbuild]

A new Pull Request was created by @kpedro88 (Kevin Pedro) for CMSSW_8_1_X.

It involves the following packages:

CalibFormats/HcalObjects

@ghellwig, @cerminar, @cmsbuild, @franzoni, @mmusich, @davidlange6 can you please review it and eventually sign? Thanks.
@ghellwig, @tocheng this is something you requested to watch as well.
@slava77, @smuzaffar you are the release manager for this.

cms-bot commands are list here #13028

[kpedro88]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

-1
Tested at: UNKNOWN
I was not able to find a release to test this PR. See the Jenkins logs for more details.

[kpedro88]

@slava77 @smuzaffar that's a new one for me... any suggestions?

[smuzaffar]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/14105/console
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/14106/console

[kpedro88]

@cmsbuild please test

[kpedro88]

(previous round of tests seems to have gotten stuck)

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/14144/console

[cmsbuild]

+1
Tested at: 80eb5a6
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-15214/14144/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-15214/14144/summary.html

[kpedro88]

@mmusich comparison looks good to me, and @bsunanda confirmed in a private test that this fixes the slowdown we observed with the fine-segmented BH.