3 ms·

Any programmer with a competent faculty for science can see that your experiment is flawed: 1. too many indepedent variables: comparing two different compilers

Any programmer with a competent faculty for science can see that your experiment is flawed: 1. too many indepedent variables: comparing two different compilers on two different platforms on two different architectures?!! 2. and then you compare performances without equal consideration of the problem size for n! your conclusions are premature, sir, your analysis is conjecture and yet you dare use the word "primitive". for instance, are you aware that Blas uses Fortran whose lack of pointer aliasing effects in memory could be causing the disparity here? have you considered that certain interprocedural optimizations have been affected by not having seperate translation units for your tests?! you have also added debugging flags to the compilers further slowing the BLAS routines with more debugging cruft!?! gah! for these reasons above and the flaunted use of architecture specific intrinsics, your post stands accused! make revisions and then also see how blas performs using a better algorithm with possibly fewer aliasing effects see http://m.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=zvmmf&paperid=4056&option_lang=rus http://m.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=zvmm... begone from this thread! use proper profiling tools. learn c! fix this violence to science and injustice!!!

hairy_man674 10y ago
68 upvotes?! 68 people who are too readily given to copy pasted bit twiddling hacks with complete disregard for application of computer scientific method! 68 people who are probably javascript and .NET developers who make $$$$$ while i make c for C.
attractivechaos 10y ago
> 2. and then you compare performances without equal consideration of the problem size for n! All the different implementations are compared on the same condition: same n, same compiler and same machine. > are you aware that Blas uses Fortran Wrong. uBLAS and Eigen are written purely in C++. OpenBLAS is a mixture of C and ASM. They have nothing to do with Fortran. > you have also added debugging flags to the compilers further slowing the BLAS routines with more debugging cruft!? By debugging flags, you mean "-g"? No, -g should not affect the performance (maybe a tiny bit on loading the executable, but that is negligible). Get rid of -g, and you will get essentially the same result. > you dare use the word "primitive" Yes, I dare, because uBLAS is just that bad and should be trashed. Prove me wrong with your benchmarks. Let number speak for itself.
- hairy_man674 10y ago
  The burden of proof is on you to prove otherwise, sir.

hairy_man674 10y ago

68 upvotes?! 68 people who are too readily given to copy pasted bit twiddling hacks with complete disregard for application of computer scientific method! 68 people who are probably javascript and .NET developers who make $$$$$ while i make c for C.

attractivechaos 10y ago

> 2. and then you compare performances without equal consideration of the problem size for n! All the different implementations are compared on the same condition: same n, same compiler and same machine. > are you aware that Blas uses Fortran Wrong. uBLAS and Eigen are written purely in C++. OpenBLAS is a mixture of C and ASM. They have nothing to do with Fortran. > you have also added debugging flags to the compilers further slowing the BLAS routines with more debugging cruft!? By debugging flags, you mean "-g"? No, -g should not affect the performance (maybe a tiny bit on loading the executable, but that is negligible). Get rid of -g, and you will get essentially the same result. > you dare use the word "primitive" Yes, I dare, because uBLAS is just that bad and should be trashed. Prove me wrong with your benchmarks. Let number speak for itself.

hairy_man674 10y ago
The burden of proof is on you to prove otherwise, sir.