A[:, indx] currently makes a copy. Try replacing it with slice(A, :, indx) (if you're on julia 0.4) or use ArrayViews if you're on julia 0.3.
For performance questions, if you aren't using the tools advertised at http://docs.julialang.org/en/release-0.3/manual/performance-tips/ you will likely find them to be a big help. --Tim On Wednesday, February 11, 2015 07:25:38 AM Kyunghun Kim wrote: > Hi, all. > > I am sorry that I am writing repeating these questions again. (performance > compared to ~) > I have some signal processing code written in MATLAB, and rewriting the > code with Julia. > > The signal processing function take about 1024 x 1024 floating number array > as input called in loop about 100~1000 times. > Here is core function of algorithm: > > MATLAB version: https://gist.github.com/moon6pence/3e60772943f206842d31 > > >0.16 sec per each call > > Julia version: https://gist.github.com/moon6pence/4b43c63cb4240b31ea10 > > >1.4 sec per each call > > Not only julia code is unusually slow, but MATLAB code is also unusually > fast. > (Naive C++ implementation of this code takes 100~200 sec, maybe MATLAB JIT > compiler is doing very well in SIMD) > > I will dig up this julia code line-by-line to find which line takes much > time. > But before then, I want get this code checked if there is any mistake on > code for performance. (or give me tips for vectorized code) > > Thanks.
