ROOT Version: 6.24/04 Platform: OSX 20.26.7, Catalina Compiler: precompiled installation I noticed that my python script with ROOT libraries is running much slower on Mac (10.16.7, Catalina) then on RedHat7. I found that it is connected with using ROOT.Math library. I wrote simple script to test…

Hello, Is this reproducible also in C++?

Random guess, but as I expect math.sqrt and ROOT.Math.sqrt to both be optimized to death, I think what you might be measuring is the overhead of calling C++ functions via PyROOT compared to calling standard Python C extension modules (I don’t know why that might be slower on Mac than on RedHat).

You can try importing sqrt from ROOT.Math and calling it directly from the loop: import ROOT from ROOT.Math import sqrt as root_sqrt for i ... r = root_sqrt(2.)

I did not test it myself but my friend did and said that c++ works fast.

It is not the case. I have another laptop with python2.7 and ROOT v6.14. It works very fast: math.sqrt(2.). 0.02 sec ROOT.Math.sqrt(2.) 0.2 sec As I wrote with with python3.9.6 and ROOT v6.24 math.sqrt(2.). 0.02 sec ROOT.Math.sqrt(2.) 12.8 sec

[image] etejedor: from ROOT.Math import sqrt as root_sqrt I did it but got the error message sqrt3=root.sqrt(2.) NameError: name ‘root’ is not defined

[image] diemort: from ROOT import TFile In my case adding the line from ROOT import TFile does nothing. CPU time is the same

[image] valkuba: As I wrote with with python3.9.6 and ROOT v6.24 math.sqrt(2.). 0.02 sec ROOT.Math.sqrt(2.) 12.8 sec Yes I understand, my point was that it’s probably not ROOT’s implementation of sqrt that’s slow(er), but the machinery required to call the C++ sqrt function from Python, sor…

Sorry for typo. Yes, this helps, 0.06 seconds instead of 13 seconds. This is interesting suggestion and observation. It was just a example. In the real program I am using another packages. ROOT.Math.PxPyPzMVector Do I need to import all of them one by one?

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Python with ROOT.Math libraries is very slow on MAc

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