# Converting - for loop to Cuarray dot syntax
**URL:** https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679
**Category:** General Usage
**Tags:** cuarrays
**Created:** [February 20, 2021, 3:19pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679 "2021-02-20T15:19:52Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@naviinkapoor](https://discourse.julialang.org/u/naviinkapoor)
#### Post date: [February 20, 2021, 3:19pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/1 "2021-02-20T15:19:52Z")
Hello Everyone,
I need help to convert the below code to carry dot syntax
From
for i=1:j
a[i] = a[i] + a[i+j]
end
I converted it to a[1:j].=a[1:j].+a[1:j+j] , but it is not working
---
### Author:  [@dpsanders](https://discourse.julialang.org/u/dpsanders)
#### Post date: [February 20, 2021, 3:29pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/2 "2021-02-20T15:29:24Z")
You are adding arrays of different lengths.
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### Author:  [@naviinkapoor](https://discourse.julialang.org/u/naviinkapoor)
#### Post date: [February 20, 2021, 3:36pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/3 "2021-02-20T15:36:02Z")
I got it, but is there any way to implement this in Cuarray dot syntax?
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### Author:  [@simeonschaub](https://discourse.julialang.org/u/simeonschaub)
#### Post date: [February 20, 2021, 3:39pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/4 "2021-02-20T15:39:50Z")
> [@naviinkapoor](#):
>
> converted it to a[1:j].=a[1:j].+a[1:j+j] , but it is not working
You may be looking for `a[1:j].=a[1:j].+a[(1:j).+j]`. `+` takes precedence over `:`, so `1:j+j` is equivalent to `1:(j+j)` and therefore probably not what you meant.
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### Author:  [@gustaphe](https://discourse.julialang.org/u/gustaphe)
#### Post date: [February 20, 2021, 3:42pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/5 "2021-02-20T15:42:24Z")
Your error is in `1:j+j`. This evaluates to `1:(j+j)`. You can solve it by writing it as `(1:j).+j`.
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### Author:  [@dpsanders](https://discourse.julialang.org/u/dpsanders)
#### Post date: [February 20, 2021, 3:43pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/6 "2021-02-20T15:43:36Z")
What do you mean by CuArray dot syntax?
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### Author:  [@dpsanders](https://discourse.julialang.org/u/dpsanders)
#### Post date: [February 20, 2021, 3:48pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/7 "2021-02-20T15:48:50Z")
It already works with `CuArray`s:
```julia
julia> n = 5
julia> a = CuArray(fill(1, 2n));
julia> a[1:n] .+= a[n+1:2n];
julia> a
10-element CuArray{Int64, 1}:
2
2
2
2
2
1
1
1
1
1
```
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### Author:  [@naviinkapoor](https://discourse.julialang.org/u/naviinkapoor)
#### Post date: [February 20, 2021, 3:59pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/8 "2021-02-20T15:59:24Z")
> [@gustaphe](#):
>
> `(1:j).+j` .
Perfect, thanks it is working:)
---
### Author:  [@naviinkapoor](https://discourse.julialang.org/u/naviinkapoor)
#### Post date: [February 20, 2021, 3:59pm UTC](https://discourse.julialang.org/t/converting-for-loop-to-cuarray-dot-syntax/55679/9 "2021-02-20T15:59:37Z")
Thanks it is also working:)