# Parrallel programming2
**URL:** https://discourse.julialang.org/t/parrallel-programming2/42027
**Category:** Performance
**Tags:** question
**Created:** [June 25, 2020, 7:33am UTC](https://discourse.julialang.org/t/parrallel-programming2/42027 "2020-06-25T07:33:47Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@hyacykcharel](https://discourse.julialang.org/u/hyacykcharel)
#### Post date: [June 25, 2020, 7:33am UTC](https://discourse.julialang.org/t/parrallel-programming2/42027/1 "2020-06-25T07:33:47Z")
Hello im trying to run this for loop parallel on evwery Process but still getting Error ,I Triyed it in 2 ways, can someone Help please?thanks
using Distributed
addprocs(2)
@everywhere using DistributedArrays
@everywhere using SharedArrays
A = SharedArray[{Float64}(n-1,n-1)
```
@distributed (+) for i in 1:n-2
A[i,i+1] = -1
A[i,i] = 2
A[i+1,i] = -1
end
@sync @distributed for i in 1:n-2
A[i,i+1] = -1
A[i,i] = 2
A[i+1,i] = -1
end
```
ERROR: LoadError: SingularException(1)
Stacktrace:
[1] ldiv!(::Diagonal{Float64,Array{Float64,1}}, ::Array{Float64,2}) at D:\buildbot\worker\package\_win64\build\usr\share\julia\stdlib\v1.4\LinearAlgebra\src\diagonal.jl:575
---
### Author:  [@jishnub](https://discourse.julialang.org/u/jishnub)
#### Post date: [June 25, 2020, 8:14am UTC](https://discourse.julialang.org/t/parrallel-programming2/42027/2 "2020-06-25T08:14:26Z")
The code runs for me, so you must be doing something else that is resulting in the issue. Could you please post a self-contained example that doesn’t work? You might want to run this example in a separate julia session to verify that this works.
```julia
julia> using Distributed
julia> addprocs(2)
2-element Array{Int64,1}:
2
3
julia> @everywhere using SharedArrays
julia> n=10
10
julia> A = SharedArray{Float64}(n-1,n-1);
julia> @distributed (+) for i in 1:n-2
A[i,i+1] = -1
A[i,i] = 2
A[i+1,i] = -1
end
-8
julia> A
9×9 SharedArray{Float64,2}:
2.0 -1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
-1.0 2.0 -1.0 0.0 0.0 0.0 0.0 0.0 0.0
0.0 -1.0 2.0 -1.0 0.0 0.0 0.0 0.0 0.0
0.0 0.0 -1.0 2.0 -1.0 0.0 0.0 0.0 0.0
0.0 0.0 0.0 -1.0 2.0 -1.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0 -1.0 2.0 -1.0 0.0 0.0
0.0 0.0 0.0 0.0 0.0 -1.0 2.0 -1.0 0.0
0.0 0.0 0.0 0.0 0.0 0.0 -1.0 2.0 -1.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 -1.0 0.0
```
---
### Author:  [@hyacykcharel](https://discourse.julialang.org/u/hyacykcharel)
#### Post date: [June 25, 2020, 8:33am UTC](https://discourse.julialang.org/t/parrallel-programming2/42027/3 "2020-06-25T08:33:53Z")
Thanks for the reply here ist the complete code
# FD-Solution of Poisson-Equation on [0,1]
using Distributed
addprocs(1)
@everywhere n=10
@everywhere using LinearAlgebra
@everywhere using SharedArrays
@everywhere using DistributedArrays
using Plots
@everywhere function Plot\_Poisson\_Equation(n)
```
A = SharedArray{Float64}(zeros(n-1,n-1))
```
#creating a 3 Diagonal Matrix
```
@distributed (+) for i in 1:n-2
A[i,i+1] = -1
A[i,i] = 2
A[i+1,i] = -1
end
A[n-1,n-1] = 2
return A
```
end
@everywhere function secondpar\_b(n)
```
h = 1/n
b = h^2 * ones(n-1,1)
```
end
#calling each function on separate process (Parallel)
end
A = fetch(@spawnat 1 Plot\_Poisson\_Equation(n))
b = fetch(@spawnat 2 secondpar\_b(n))
u = A\b
#adding boundary condition
u = [0 u’ 0]’
h = 1/n
plot(collect(0:h:1),u,background\_color= BGR(0.1,0.1,0.1),lw=3)
xlabel!(“x”)
ylabel!(“y”)
title!(“FD-Solution of Poisson-Equation on [0,1]”)
---
### Author:  [@johnh](https://discourse.julialang.org/u/johnh)
#### Post date: [June 25, 2020, 10:46am UTC](https://discourse.julialang.org/t/parrallel-programming2/42027/4 "2020-06-25T10:46:40Z")
That looks fishy to me.