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With that, on i686 Linux, gcc -O3 I get:
sorted array: min_element,max_element:1.89 minVal=0,maxVal=99999999 min_max: accumulator:0.45 minVal=0,maxVal=99999999 min_max: minmax_element:0.48 minVal=0,maxVal=99999999 min/max handcoded:0.79 minVal=0,maxVal=99999999 random array: min_element,max_element:1.8 minVal=7,maxVal=2147483611 min_max: accumulator:0.36 minVal=7,maxVal=2147483611 min_max: minmax_element:0.6 minVal=7,maxVal=2147483611 min/max handcoded:0.71 minVal=7,maxVal=2147483611
And with icc -O3:
sorted array: min_element,max_element:0.74 minVal=0,maxVal=99999999 min_max: accumulator:0.51 minVal=0,maxVal=99999999 min_max: minmax_element:0.48 minVal=0,maxVal=99999999 min/max handcoded:0.51 minVal=0,maxVal=99999999 random array: min_element,max_element:0.75 minVal=7,maxVal=2147483611 min_max: accumulator:0.51 minVal=7,maxVal=2147483611 min_max: minmax_element:0.68 minVal=7,maxVal=2147483611 min/max handcoded:0.51 minVal=7,maxVal=2147483611
I'm quite surprised by these numbers, in that: - gcc sometimes beats icc - gcc's accumulator looks significantly faster on random data than sorted data (indeed, on random it's the fastest thing of all).
I'd guess that minmax_element is faster on sorted data because branch prediction works better there.
Nevertheless, it's clearly very different from your results, in that we have opposite fastest and slowest methods. I suspect you're missing some crucial optimization (probably the inlining of a function somewhere in accumulator).
Your results are really different from my one, but normally I would say more expected. I can't find any wrong settings at the moment in my project. May be it helps when I post the command line parameters: Compiler settings: /GL /D "WIN32" /D "_CONSOLE" /D "_SECURE_SCL=0" /D "NDEBUG=1" /D "_UNICODE" /D "UNICODE" /FD /EHsc /MD /Yu"stdafx.h" /Fp"Release\Statistic.pch" /Fo"Release\\" /Fd"Release\vc90.pdb" /W3 /nologo /c /Zi /TP /errorReport:prompt Linker settings /OUT:"D:\projects\sandbox\BoostTests\Release\Statistic.exe" /INCREMENTAL:NO /NOLOGO /MANIFEST /MANIFESTFILE:"Release\Statistic.exe.intermediate.manifest" /MANIFESTUAC:"level='asInvoker' uiAccess='false'" /DEBUG /PDB:"d:\projects\sandbox\BoostTests\release\Statistic.pdb" /SUBSYSTEM:CONSOLE /OPT:REF /OPT:ICF /LTCG /DYNAMICBASE:NO /MACHINE:X86 /ERRORREPORT:PROMPT kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib BTW if I compile your program with debug I get an compile error : error C2664: 'std::_Vector_iterator<_Ty,_Alloc>::_Vector_iterator(const std::_Vector_iterator<_Ty,_Alloc> &)': can't convert from 'int *const ' to 'const std::_Vector_iterator<_Ty,_Alloc> &' in the line std::pair< std::vector<int>::iterator, std::vector<int>::iterator > result = boost::minmax_element(data.begin(), data.end()); Any ideas? Thanks Hansjörg