# Parallelizing if loops
**URL:** https://discourse.julialang.org/t/parallelizing-if-loops/90095
**Category:** New to Julia
**Tags:** question
**Created:** [November 11, 2022, 5:14am UTC](https://discourse.julialang.org/t/parallelizing-if-loops/90095 "2022-11-11T05:14:34Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@iangilan](https://discourse.julialang.org/u/iangilan)
#### Post date: [November 11, 2022, 5:14am UTC](https://discourse.julialang.org/t/parallelizing-if-loops/90095/1 "2022-11-11T05:14:34Z")
How could I parallelize the following for loop including if condition?
I’d like to use a different thread for each A,B,C and D.
```julia
for i=1:N
if x[i]>0 && y[i]>0
do A
elseif x[i]>0 && y[i]<0
do B
elseif x[i]<0 && y[i]>0
do C
else
do D
end
end
```
---
### Author:  [@Mason](https://discourse.julialang.org/u/Mason)
#### Post date: [November 11, 2022, 5:23am UTC](https://discourse.julialang.org/t/parallelizing-if-loops/90095/2 "2022-11-11T05:23:45Z")
> [@iangilan](#):
>
> I’d like to use a different thread for each A,B,C and D.
But only of them is going to run, so isn’t this always single threaded?
---
### Author:  [@iangilan](https://discourse.julialang.org/u/iangilan)
#### Post date: [November 11, 2022, 5:25am UTC](https://discourse.julialang.org/t/parallelizing-if-loops/90095/3 "2022-11-11T05:25:25Z")
A, B, C and D are independent.
---
### Author:  [@iangilan](https://discourse.julialang.org/u/iangilan)
#### Post date: [November 11, 2022, 5:28am UTC](https://discourse.julialang.org/t/parallelizing-if-loops/90095/4 "2022-11-11T05:28:17Z")
I mean I want to use 1 thread for each condition, so maybe for loop is not appropriate. If that’s the case, I am looking for an alternative way to solve this.
---
### Author:  [@Mason](https://discourse.julialang.org/u/Mason)
#### Post date: [November 11, 2022, 5:51am UTC](https://discourse.julialang.org/t/parallelizing-if-loops/90095/5 "2022-11-11T05:51:43Z")
Sure they can be independant, but if you write
```julia
if cond1
A()
elseif cond2
B()
else
C()
end
```
only one of those blocks of code actually runs, determined by the condition.
```julia
julia> if true
println("A")
elseif true
println("B")
else
println("C")
end
A
julia> if false
println("A")
elseif true
println("B")
else
println("C")
end
B
julia> if false
println("A")
elseif false
println("B")
else
println("C")
end
C
```
There’s no notion of parallelizing an `if` statement, because multiple things aren’t being run
---
### Author:  [@goerch](https://discourse.julialang.org/u/goerch)
#### Post date: [November 11, 2022, 6:07am UTC](https://discourse.julialang.org/t/parallelizing-if-loops/90095/6 "2022-11-11T06:07:18Z")
> [@iangilan](#):
>
> ```julia
> for i=1:N
>
> ```
```julia
Threads.@threads for i=1:N
```
does the job for me.
---
### Author:  [@Mason](https://discourse.julialang.org/u/Mason)
#### Post date: [November 11, 2022, 6:49am UTC](https://discourse.julialang.org/t/parallelizing-if-loops/90095/7 "2022-11-11T06:49:31Z")
Ohh, if the OP is trying to multithread the loop, then yes you can do that. I think I just misunderstood what they were asking for originally, sorry for the noise @iangilan.