29th ROOT Parallelism, Performance and Programming Model

Thursday 18 Jan 2018, 16:00 → 18:00 Europe/Zurich

4/S-030 (CERN)

Danilo Piparo (CERN)

Present: Enric, Guilherme, Enrico, Xavi, Lorenzo, Gerri, Philippe

Axel stresses the importance of the behaviour of TVec<T> copy.

Copy elision with templates is the natural evolution

Philippe: bidimensional collections. It is stressed how this is an aspect to be considered.

- With a wrapper, one could do it easily myV[23][-1][12]

- Now, with an external function "Project(myV, 23, -1, 12)"

 

Conclusions:

- Treating the multidimensional case is the main question to answer before buying into this

 

Round table:

- Guilherme: reviewing jira issues, working on build system and infrastructure - e.g. enhance PR infrastructure

- Enric: focussed on PyROOT - Fixed leak when accesing TTree branch which is a collection, preparing a chart of most appealing features to implement in PyROOT, study cppyy and its interplay with the present PyROOT.

- Lorenzo: fitting in parallel and plugin manager issue, CMS merge PR which was a fix of the TMinuit minimiser. TMinuit and not TMinuit2 is a consequence of the plugin manager bug

- Enrico: looking at how reducing calls to ProcessLine&co in TDF since jitting has a cost, especially in terms of memory. This is tricky because after a filter/define call one has to return a node to the user - this is implementation. At user level, the issue is the Define for which we need the type of the returned quantity.

- Philippe, Gerri, Xavi NTR

16:00 → 16:35 Express easily common operations on collections with VecOps

Speakers: Danilo Piparo (CERN), Enric Tejedor Saavedra (CERN), Enrico Guiraud (CERN, University of Oldenburg (DE))

VecOps on Github

VecOps.pdf

16:35 → 17:00 Round Table and Discussion

• Open issues about parallelism
• Summer/GSoC/Openlab students