-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Pascal,
I would think that a good programmer can often optimise better for a specific problem than a general purpose library would. For example I implemented a peak search for diffraction images which is about an order of magnitude faster than ImageMagick based on the same idea (it took me two weeks, though ;-) ). I am surprised you suggest a library for trigonometric functions - I thought that for long intel CPUs have a special coprocessor for those and that compilers would directly make use of this. Best, Tim On 05/09/2014 05:38 PM, Pascal wrote: > Le 09/05/2014 15:36, Adam Ralph a écrit : >> >> Can it be parallelized? That is how you reduce run-time. One of >> the tests matrix-matrix multiplication has been successfully >> speeded up by using GPUs. CUDA is the language used for this, >> which is a derivative of C. To be fair you only see the benefit >> for really large matrices, smaller ones which actually be slower >> on GPUs. > > Talking about matrix multiplication, the benchmark is biased as > they used openblas. The core multiplication is done in assembly. So > it's probably machine code rules! > > mathematica and octave probably use mkl, same as openblas. This is > the reason why fortran, C, julia, mathematica and matlab perform > the same. They are all linked to mkl or openblas. > > There is a fantastic link on the optimization on general matrix > matrix mutiplication: > <http://wiki.cs.utexas.edu/rvdg/HowToOptimizeGemm> > > Python uses numpy which is a wrapper around lapack aka fortran... > Same for R. I think octave too. > > One general advice to give would be not try to optimise, use a > library instead. > > openblas/mkl/acml for linear algebra fftw for fourier transform > sleef for trigonometric functions and other math functions mixmax > for random numbers And so on... > > Pascal > - -- - -- Dr Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with Icedove - http://www.enigmail.net/ iD8DBQFTbPn1UxlJ7aRr7hoRAjB4AKDs2uzifBDUSkR6I2b3TS4tyXBi4gCgj7fl 5y50f32US65Wqggku1dRR4Y= =Od8Y -----END PGP SIGNATURE-----
