Thanks for the reply.
I think this still suffers from the same issue of allocating tmp every
iteration through the loop. I only need to store the output of qr() if
certain criteria are met. Then I do as you recommended and push it into a
array. Consider the following
function test_qr3(iters)
tmp=rand(3,3)
a=Array{Array{Float64,2},1}
for i=1:iters
a=qr(tmp)
end
end
julia> @time test_qr3(100000)
elapsed time: 0.474589094 seconds (147200224 bytes allocated)
julia> @time test_qr3(200000)
elapsed time: 0.90662408 seconds (294400224 bytes allocated)
While this is a trivial example, there should be a way to make it so that
'a' is not re-alloacted each time through the loop. Or maybe the allocation
is happening within qr()?
Thanks
On Tuesday, October 7, 2014 3:29:01 PM UTC-7, Max Suster wrote:
>
>
> You could try this.
>
> a= Array{Float64,2}[]
> b= Array{Float64,2}[]
>
> function test_qr(a,b)
>
> for i=1:100000
> tmp = qr(rand(3,3))
> push!(a,tmp[1])
> push!(b,tmp[2])
> end
>
> end
>
> julia> size(a,1)
> 100000
>
> julia> size(b,1)
> 100000
>
>
> On Tuesday, October 7, 2014 10:17:07 PM UTC+2, Ryan Young wrote:
>>
>> Hello,
>>
>> I am working on optimizing a code that looks at 3D deformation fields.
>> At one point I have to take the QR decompositions at many points. My
>> problem is that regardless of how I pre-allocate my variables to store the
>> results of the QR, they are allocated each time through the loop. I tried
>> to use the qrfact! method but found it suffered from the same problem. Any
>> help in getting around this would be great. A basic function that has the
>> same problem is below.
>>
>> function test_qr()
>> tmp=rand(3,3)
>> a=Array(Float64,2)
>> b=Array(Float64,2)
>>
>> for i=1:100000
>> a,b=qr(tmp)
>> end
>>
>> end
>>
>
