# How to use parallel computing or GPU to make calculations fasterwhen the M=10000

**URL:** <https://discourse.julialang.org/t/how-to-use-parallel-computing-or-gpu-to-make-calculations-fasterwhen-the-m-10000/34623>\
**Category:** GPU\
**Tags:** question\
**Created:** [February 14, 2020, 1:12pm UTC](https://discourse.julialang.org/t/how-to-use-parallel-computing-or-gpu-to-make-calculations-fasterwhen-the-m-10000/34623 "2020-02-14T13:12:24Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![11125](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/11125/32/11648_2.png) [@11125](https://discourse.julialang.org/u/11125)\
**Post date:** [February 14, 2020, 1:12pm UTC](https://discourse.julialang.org/t/how-to-use-parallel-computing-or-gpu-to-make-calculations-fasterwhen-the-m-10000/34623/1 "2020-02-14T13:12:24Z")

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using CuArrays,CUDAnative,CUDAdrv,BenchmarkTools  
N = 3  
k = ones(N,N)\*5  
M = 100

rho = zeros(N,N)  
aa = range(-5,5,length=N)  
K = zeros(N,N)  
A = repeat(-aa’,N,1)  
B = repeat(aa,1,N)  
C=ones(N,N)_-10  
phi = repeat(range(0,2_pi,length=M),1,M)  
theta = repeat(range(0,pi/2,length=M),1,M)’

Rho = zeros(M,M)  
Ave\_Energy = ones(N,N)\*pi/N^2  
junyundu = 0  
f = zeros(N,N)  
function getnum(rho,K,f,A,B,C,phi,theta)  
while junyundu \< 0.9  
goal\_E = ones(N,N)/N^2  
number\_E = zeros(N,N)  
E = zeros(N,N)

```
    Threads.@threads for i = 1:M
        Threads.@threads for j = 1:M
                f .= @views (A[:, :].^2 .+ B[:,:].^2 .+ C[:, :] .^2).^0.5
                K .= @views 2 .* k[:, :] .+ f[:,:]
                rho .= @views (K[:, :] .^2 .- f[:, :].^2) ./ (2 .* (K[:, :] .- A[:, :] .* sin(theta[i, j]) .* cos(phi[i, j]) .-
                            B[:, :] .*sin(theta[i, j]) .* sin(phi[i, j]) .- C[:, :] .* cos(theta[i, j])))

        Rho[i, j] = maximum(maximum(rho[:]))
        FF = findall(x->x .== maximum(maximum(rho)),rho)
        number_E[FF] = number_E[FF] .+ 1/length(FF)
        end
    end
    
E = number_E/(M*M)*pi
Var = goal_E - E
da = findall(x->x > 0, Var)
xiao = findall(x->x < 0, Var)
Var = Ave_Energy - E
fangcha = sum(sum(Var.^2))

if Var == 0
    k .= @views k[:, :] .+ 0
else
    k .= @views k[:, :] .+ Var[:, :] .* 0.1
end

qa = maximum(maximum(E))
qb = minimum(minimum(E))
qc = sum(sum(E))/(N*N)
global junyundu = 1-(qa-qb)/qc
println(meannum)
end

```

end

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<div class="post-metadata">

**Author:** ![jpsamaroo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jpsamaroo/32/46804_2.png) [@jpsamaroo](https://discourse.julialang.org/u/jpsamaroo)\
**Post date:** [February 14, 2020, 4:52pm UTC](https://discourse.julialang.org/t/how-to-use-parallel-computing-or-gpu-to-make-calculations-fasterwhen-the-m-10000/34623/2 "2020-02-14T16:52:03Z")

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Can you please place your code between triple backticks (``` my code goes here ```), so that it’s easier to read your posted code?

Also, what exactly is your question? Do you have benchmarks of your code that show that it isn’t performing as fast as you’d expect? Do you have a hot loop that you need help optimizing?