Stefan,
I have a function which loads the data structure, loads the actual data
file and defines frame numbers, determines PACKSIZE etc.
But to test the performance I did not use the function for but as in global
scope.
Tom, I will look up your suggestion.
Thanks
On Wednesday, December 2, 2015 at 12:56:48 AM UTC-5, Rajn wrote:
>
> I am reading a binary file with a structure. Matlab takes long and I
> wanted to run Julia for speed improvement.
> It reads camera frames, each with certain bytesize and each frame
> consisting of parameters of certain byte size and Type.
>
> frames: is declared Int64 and runs from 1:frames
> PACKSIZE is declared Int64 and is constant
> key_ind is Int16 and is a vector. This denotes the parameters which
> defines the frames. There are 200 but I am only interested in 3.
> Type declared Type as: 1x3 Array of Int16, Int16, Float64...
> Num as Int64 and 3x1 elements and each is 1. This says that there are only
> 1 elements of each Type in a frame.
>
> This is where I want to store the data...
> dCell = 3x1 Array{Any,2} of Array{Int16}(1xframes)
> Array{Int16}(1xframes) and Array{Float64}(1xframes)
>
> each camera frame is of PACKSIZE in bytes.
>
> To summarize I have declared the type of each variable before I start the
> read process.
>
> #Read and assemble the data structured as series of Int16,Int16,Float64...
> for j=1:length(frames);
> Pos = frames[j]*PACKSIZE ;
> for k=1:size(key_ind,1)
> seek(fid,Pos[k]);
> value = read(ifov_fid, Type[k][1],Num[k]); #Num[k] is all ones.
> dCell[k][:,j]=value;
> end
> end
>
> For 500,000 frames it takes as much time as Matlab. Not getting warnings
> or errors but would like to know how to improve the code for speed or
> efficiency.
>
> I am not familiar with binary read and was wondering if this is 'normal'
> and one cannot do any better? If I were to write this in C would it also
> take the same amount (maybe because of my sloppy code)? I should perhaps
> give details on the processor I use but because I am only comparing Matlab
> with Julia - and I am not doing any parallelization - I think that OS
> details are not important?
> In the Matlab code I am declaring few variables types but not being very
> careful as I am in with Julia.
> I am not reading the entire structure i.e., key_ind =1:3 of 200, each with
> different byte size. Therefore, I am not providing @time but if curious it
> is ~30-45 seconds for 500000 frames. The inner for-loop takes about
> ~0.00007 seconds.
> Thanks
>
>
>
