On Monday 30 August 2004 18:33, John Lamb wrote:
Stefan Hundhammer wrote:
OK, thanks, that's a very informative site.
But according to the charts there, there is hardly any difference in performance, right? Sometimes even C/C++ appears to be faster.
Or am I reading those charts wrong? An interesting paper. I would probably ignore the details of the charts however as the results date from 1996!
No, though there may be other examples where F is actually faster, depending on the usual things, how it's compiled, what number-crunching is done etc. Agreed
There are still F libraries such as ATLAS that are reputedly better than the C equivalent. This is rather odd. ATLAS is most definitely written in C. It has both F77 and C interfaces. ATLAS is fast because of it's high quality algorithms and tuning ability.
That said if you are doing ordinary numeric computation I don't think you will notice any performance differences between F77/C/C++. If you are "fancy stuff" other factors will probably be more important. Compiler availability/strength, existing code etc etc In terms of performance optimisation one of the biggest advantages Fortran has is the lack of pointers and therefore the lack off possible aliases. C/C++ compilers have to employ comlex alias optimisation analysis. Here C++ is significantly better then C. Reference types (instead of pointers), the use of 'const', and inline member functions all help the complier. Michael