I have looked the codes of cumsum and friends. They are still using old-style slice-based implementation, instead of the new cache friendly ways (the way we are implementing reduction).
Not sure how quickly these will be resolved. If this is not addressed in 2 - 3 weeks, I may take a shot to reimplement them. Dahua On Friday, June 20, 2014 5:53:44 PM UTC-5, Charles Santana wrote: > > Hi again, > > Just to let you know about the issue I just opened in Github: > > https://github.com/JuliaLang/julia/issues/7342 > > Thank you for everything! > > Best, > > Charles > > > On Fri, Jun 20, 2014 at 10:07 PM, Charles Novaes de Santana < > charles...@gmail.com <javascript:>> wrote: > >> Thank you, Dahua! >> >> I will open an issue in Github as suggested by you. In meanwhile I will >> see if by using sum I can get a better performance. >> >> Best, >> >> Charles >> >> >> On Fri, Jun 20, 2014 at 5:54 PM, Dahua Lin <lind...@gmail.com >> <javascript:>> wrote: >> >>> The cumsum / cummax / cummin / cumprod, etc have suboptimal performance >>> currently, which are about 20x slower than the sum/prod etc (which we spent >>> a lot of efforts to optimize and tune). >>> >>> Please open an issue in Github, and we will try to address this problem >>> later. >>> >>> Dahua >>> >>> >>> On Friday, June 20, 2014 10:15:55 AM UTC-5, Charles Santana wrote: >>>> >>>> Dear Julia users, >>>> >>>> First of all, Congratulations for this amazing community and for this >>>> impressive language! I used to program in C++ and in R, I started to >>>> program with Julia 3 months ago and it has changed my life for better!! >>>> Thank you!! >>>> >>>> By checking the profile of a program we are developing we noted that >>>> the "bottleneck" seems to be in a cumulative sum along a dimension in a >>>> matrix, for what we use the function cumsum. >>>> >>>> We are doing something like this: >>>> >>>> DI = rand(5,5); >>>> Dc = cumsum(DI,2); >>>> >>>> Just to try to clarify what we are doing: Imagine that Matrix DI(i,j) >>>> represents the probability of an individual to move from a site i to a >>>> site >>>> j. We use Dc to determine to which site an individual in site i will move, >>>> by generating a random number between 0 and maximum(Dc[i,:]). That means, >>>> we are trying to perform a Multinomial Distribution. >>>> >>>> Do you know an alternative to cumsum or do you indicate a good way to >>>> use this function. >>>> >>>> Thanks in advance for any help! >>>> >>>> Best regards, >>>> >>>> Charles Novaes de Santana >>>> -- >>>> Um axé! :) >>>> >>>> -- >>>> Charles Novaes de Santana, PhD >>>> http://www.imedea.uib-csic.es/~charles >>>> >>> >> >> >> -- >> Um axé! :) >> >> -- >> Charles Novaes de Santana, PhD >> http://www.imedea.uib-csic.es/~charles >> > > > > -- > Um axé! :) > > -- > Charles Novaes de Santana, PhD > http://www.imedea.uib-csic.es/~charles >
