hi,
"eric" == eric <eric@scipy.org> writes:
eric> Hey Pearu, <snip Fortran compared to Blitz> >> > > Iterations took 6.12530398369 seconds. > > Fortran >> iterations took 3.15447306633 seconds. eric> I've rewritten the code in C++ as quickly as I know how and eric> added a few optimizations. It has the same errors as the eric> previous example, but, again, is useful for eric> benchmarking. (maybe Prabhu will fix my bugs in this code eric> also. :) The results are as follows: I've added all the stuff to my version of the code -- I still have to remove the mayavi dependency and maybe clean it up a bit but here are some prelim results. I have the following solution procedures. (a) slow Python - normal for loops and stuff. (b) numeric -- just there for testing the speed the results will be different since it uses temporaries. (c) blitz -- this uses the silly way to compute the error. (d) inline -- thanks to Eric's code slightly modfied. (e) fastinline -- Eric's new version (the only bug was that err should be set to zero before the loop). (f) fortran -- This is Pearu's version pretty much verbatim. (1) I made pretty sure that the output of weave/inline/fastinline/fortran are all very much alike. I found that there is some loss of precision in the fortan code but the results are pretty much identical. The errors were different by very small numbers. For a 500 by 500 grid I computed a few iterations using weave/inline/fastinline and compared them with the fortan results and they are the same to within 1 part in 1e-15 or something. (2) Here are the results of speed tests. I create a 500x500 grid and run it for 100 iterations. I do two runs and average the results. Just for the heck of it I ran the slow time step for 5 iterations multiplied the result by 20 to get total time for 100 iterations. slow: 1847.60 s == (time for 5 iterations)*20 numeric: 29.5 s blitz: 9.75 s inline: 4.60 s fortran: 3.24 s fastinline: 2.92 s Fastinline is about 630 times faster than the normal slow for loop! Wow! unbelievable!! Obviously, more speedup can be achieved but its clear that blitz, inline, fortran and fastinline are big winners and that they are all reasonably close. inline and fortran are about 40% off which is not bad at all. fastinline is about 10% faster than fortran but the code is dirty. prabhu