MATLAB: Did CPLEX MIQP need Parallel Computing Toolbox to run cplexmiqp optimally

cplexParallel Computing Toolbox

I'am using MATLAB 2018b and adding CPLEX MIQP 12.8 to the search path:
C:\Program Files\IBM\ILOG\CPLEX_Studio128\cplex\matlab\x64_win64
In this page, it's said that CPLEX ILOG IBM automatically use all core:
https://www.ibm.com/support/knowledgecenter/en/SS9UKU_12.4.0/com.ibm.cplex.zos.help/Parameters/topics/introListAlpha.html
https://www.ibm.com/developerworks/community/forums/html/topic?id=2bf99a7e-c20b-4a87-8132-12d9b3112889
But it was said on MATLAB Mathworks forum that standard code in MATLAB didn't use parallel computing: https://www.mathworks.com/matlabcentral/answers/317128-does-matlab-use-all-cores-by-default-when-running-a-program
I use 12 core CPU with only 30% used, but 80% RAM used with 2.5 hour computation time.
My question is, did my code already use parallel computing in runing this code or do I need to buy MATLAB Parallel Computing Toolbox to run it optimally?
[x,y]=cplexmiqp(F,c,Ai,bi,Ae,be,[],[],[],x_L,x_U,IV);

Best Answer

The developerworks article is referring specifically to the case where the person is calling cplex from within a parfor loop.
You need to read Adam's answer taking into account Jan's answer and John D'Errico's answer: MATLAB can recognize some patterns of computation, and when it does and it decides the matrices are big enough, MATLAB will automatically call high performance libraries that use all available cores. This is not under user control, and MATLAB does not document exactly what is run this way or not run that way.
You can tell cplexmiqp how many cores it should use when you call it. You do not need Parallel Computing Toolbox for that.
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