Hi Stefan. I am very grateful by your attention. Each variable typed 
correctly doesn't change the perfomance. Do you have other suggestion to me?

Thanks,

-Emerson

Em quarta-feira, 26 de novembro de 2014 17h52min57s UTC-2, Stefan Karpinski 
escreveu:
>
> I wonder if \ might be type unstable.
>
> On Wed, Nov 26, 2014 at 2:49 PM, Stefan Karpinski <[email protected] 
> <javascript:>> wrote:
>
>> It turns out that doesn't actually matter but there are other unrelated 
>> ill-typed variables in the code:
>>
>> Xb, o, y, r, e, Nj, ind, q, t
>>
>>
>> I haven't determined why this is happening, but something is ill-typed 
>> here.
>>
>> On Wed, Nov 26, 2014 at 1:20 PM, Tim Holy <[email protected] 
>> <javascript:>> wrote:
>>
>>> Stefan's point is more relevant than you realize; if the type of the 
>>> variable
>>> is uncertain, the loop will be very slow. You can make that resize 
>>> operation a
>>> separate function, from which you call your main routine.
>>>
>>> --Tim
>>>
>>> On Wednesday, November 26, 2014 09:26:35 AM Emerson Vitor Castelani 
>>> wrote:
>>> > Humm, It's useful but I guess that the problem is something in loop 
>>> while...
>>> >
>>> > Em quarta-feira, 26 de novembro de 2014 15h05min03s UTC-2, Stefan 
>>> Karpinski
>>> >
>>> > escreveu:
>>> > > I'm not sure if this is the problem, but changing the type of a 
>>> variable
>>> > > in a function body causes problems for type inference. For that 
>>> reason,
>>> > > the
>>> > > first two lines of this code may cause performance issue if you call 
>>> this
>>> > > with b and c as matrices. A more Julian idiom for this is to do 
>>> something
>>> > > like this:
>>> > >
>>> > > function simplex(A::Matrix, b::Vector, c::Vector)
>>> > >
>>> > >     (m,n) = size(A);
>>> > >     ...
>>> > >
>>> > > end
>>> > > simplex(A::Matrix, b::Matrix, c::Matrix) = simplex(A, vec(b), vec(c))
>>> > >
>>> > >
>>> > > This also avoids copying the data of b and c needlessly.
>>> > >
>>> > > On Wednesday, November 26, 2014, Emerson Vitor Castelani <
>>> > >
>>> > > [email protected] <javascript:>> wrote:
>>> > >> Have you considered the example scsd8.mat?
>>> > >>
>>> > >> Em quarta-feira, 26 de novembro de 2014 14h39min14s UTC-2, Pileas
>>> > >>
>>> > >> escreveu:
>>> > >>> Result with tic() toc() at the very beginning and at the very end:
>>> > >>>
>>> > >>> elapsed time: 0.025719973 seconds
>>> > >>>
>>> > >>>
>>> > >>> Τη Τετάρτη, 26 Νοεμβρίου 2014 11:06:26 π.μ. UTC-5, ο χρήστης 
>>> Emerson
>>> > >>>
>>> > >>> Vitor Castelani έγραψε:
>>> > >>>> Well, I am tried to implement a simple version of simplex in 
>>> Julia and
>>> > >>>> I have had some troubles. In Julia, my algorithm spends about 30 
>>> sec
>>> > >>>> and in
>>> > >>>> matlab/octave 3 sec for the same problem. So, I saw some tips in 
>>> order
>>> > >>>> to
>>> > >>>> get a better performance but the best that I got in Julia was 
>>> 17-20
>>> > >>>> sec.
>>> > >>>> The codes are in attachment. I am new in Julia and the algorithms 
>>> are
>>> > >>>> little roughly implemented but they are very similar.
>>> > >>>>
>>> > >>>> Thanks
>>>
>>>
>>
>

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