Re: [julia-users] memory allocation in matrix operations

Hi Steven and Daniel, thank you so much for the corrections and suggestions! > On Sep 2, 2016, at 9:17 AM, Steven G. Johnson wrote: > > Try: > > function foo_old!(a) > for i in 1:size(a, 2) > a[:, i] /= norm(a[:, i]) > end > return a > end > >

Re: [julia-users] memory allocation in matrix operations

Try: function foo_old!(a) for i in 1:size(a, 2) a[:, i] /= norm(a[:, i]) end return a end function foo_new!(a) for i in 1:size(a, 2) s = zero(eltype(a)) @simd for j = 1:size(a,1) @inbounds s += abs2(a[j, i]) end scale_factor = 1

Re: [julia-users] memory allocation in matrix operations

Yeah, that’s what I figured, I don’t even need the sin() julia> f() = 42 f (generic function with 1 method) julia> @time f() 0.001347 seconds (141 allocations: 10.266 KB) 42 julia> @time f() 0.02 seconds (4 allocations: 160 bytes) 42 julia> @time f() 0.02 seconds (4 allocations:

Re: [julia-users] memory allocation in matrix operations

On Fri, Sep 2, 2016 at 7:41 AM, Mauro wrote: > On Fri, 2016-09-02 at 13:34, Jong Wook Kim wrote: > > Hi Yichao, what a nice idea :) > > > > But even if I write in the C++ way, @time sqrt(1) yields 5 allocations > of 176 > > bytes, and in inner loops this

Re: [julia-users] memory allocation in matrix operations

On Fri, 2016-09-02 at 13:34, Jong Wook Kim wrote: > Hi Yichao, what a nice idea :) > > But even if I write in the C++ way, @time sqrt(1) yields 5 allocations of 176 > bytes, and in inner loops this could be a bottleneck. Those are just allocations for the return value of sqrt.

Re: [julia-users] memory allocation in matrix operations

Hi Yichao, what a nice idea :) But even if I write in the C++ way, @time sqrt(1) yields 5 allocations of 176 bytes, and in inner loops this could be a bottleneck. Is this an inevitable overhead of using ccall, or is it just a bogus that I can ignore? Jong Wook > On Sep 2, 2016, at 7:14 AM,

Re: [julia-users] memory allocation in matrix operations

On Fri, Sep 2, 2016 at 7:03 AM, Jong Wook Kim wrote: > Hi, > > I'm using Julia 0.4.6 on OSX El Capitan, and was trying to normalize each > column of matrix, so that the norm of each column becomes 1. Below is a > isolated and simplified version of what I'm doing: > > function

[julia-users] memory allocation in matrix operations

Hi, I'm using Julia 0.4.6 on OSX El Capitan, and was trying to normalize each column of matrix, so that the norm of each column becomes 1. Below is a isolated and simplified version of what I'm doing: function foo1() local a = rand(1000, 1) @time for i in 1:size(a, 2) a[:,