Thanks for the hint. Getting rid of 'mx' and 'my' definitely helps.
I couldn't figure out how to implement the parallel version of tuple
adding. This is what I've got. It crashes my Julia Studio console when I
try to run it. What am I missing?
add_two_tuple(x,y) = (x[1]+y[1], x[2]+y[2], x[3]+y[3])
@parallel (add_two_tuple) for i = 1:100
x = (1,2,3)
end
I also don't have the SharedArray function (running Julia 0.2.0) so I
couldn't implement the other alternative.
Alex
On Monday, February 3, 2014 11:45:57 AM UTC-5, David Salamon wrote:
>
> You're not out of the no-slicing woods yet. Looks like you can get rid of
> `mx` and `my`
>
> for i=1:limit, j=1:int64(limit/2)
> end
>
>
>
> As far as parallelizing, you could define:
> three_tup_add(a, b, c) = (a[1] + b[1] + c[1], a[2] + b[2] + c[2], a[3] +
> b[3] + c[3])
>
> and then do a @parallel (three_tup_add) over your sample index?
>
> for that matter, why not compute the two parts of the answer directly
> rather than going via A, B, and C?
>
>
>
>
>
>
> On Mon, Feb 3, 2014 at 8:11 AM, Alex C <[email protected] <javascript:>>wrote:
>
>> Thanks. I've re-written the function to minimize the amount of copying
>> (i.e. slicing) that is required. But now, I'm befuddled as to how to
>> parallelize this function using Julia. Any suggestions?
>>
>> Alex
>>
>> function expensive_hat(S::Array{Complex{Float64},2}, mx::Array{Int64,2},
>> my::Array{Int64,2})
>>
>> samples = 64
>> A = zeros(size(mx));
>> B = zeros(size(mx));
>> C = zeros(size(mx));
>>
>> for i = 1:samples
>> Si = S[:,i];
>> Sx = Si[mx];
>> Sy = Si[my];
>> Sxy = Si[mx+my];
>> Sxyc = conj(Sxy);
>>
>> A += abs2(Sy .* Sx);
>> B += abs2(sqrt(Sxyc .* Sxy));
>> C += Sxyc .* Sy .* Sx;
>> end
>>
>> ans = (A .* B ./ samples ./ samples, C./samples)
>> return ans
>>
>> end
>>
>> data = rand(24000,64);
>> limit = 2000;
>>
>> ix = int64([1:limit/2]);
>> iy = ix[1:end/2];
>> mg = zeros(Int64,length(iy),length(ix));
>> mx = broadcast(+,ix',mg);
>> my = broadcast(+,iy,mg);
>> S = rfft(data,1)./24000;
>>
>> @time (AB, C) = expensive_hat(S,mx,my);
>>
>>
>
>
