# Avoid getting a ReshapedArray when calling reshape?

**URL:** <https://discourse.julialang.org/t/avoid-getting-a-reshapedarray-when-calling-reshape/49255>\
**Category:** New to Julia\
**Created:** [October 29, 2020, 6:16pm UTC](https://discourse.julialang.org/t/avoid-getting-a-reshapedarray-when-calling-reshape/49255 "2020-10-29T18:16:09Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![DrChainsaw](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/drchainsaw/32/8497_2.png) [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)\
**Post date:** [October 29, 2020, 6:16pm UTC](https://discourse.julialang.org/t/avoid-getting-a-reshapedarray-when-calling-reshape/49255/1 "2020-10-29T18:16:09Z")

</div>

Flux has the clever array type `Zeros` for which arithmetic operations are implemented as basically noops (well, I guess you get the idea).

The main use case is to turn of the bias term but the problem is that some ops need to reshape it and then the magic disappears:

```julia
julia> using Flux

julia> z = zeros(1000,1000);

julia> zz = Flux.Zeros(1000,1000);

julia> using BenchmarkTools
julia> @btime z+z;
  3.947 ms (2 allocations: 7.63 MiB)

julia> @btime z+zz;
  64.287 ns (1 allocation: 32 bytes)

julia> @btime z+reshape(zz,1000,:);
  3.987 ms (11 allocations: 7.63 MiB)

julia> typeof(reshape(zz,1000,:))
Base.ReshapedArray{Bool,2,Flux.Zeros{Bool,2},Tuple{}}

```

What is the best way to prevent this from happening?

Implementing `reshape` for `Zeros` is an option of course, but since it has more than a handful of methods which all specialize on the second argument one must implement all of them or else there will be ambiguity and this feels a bit brute-force-ish. I guess another option is to implement methods for `ReshapedArray` of `Zeros` but this is probably even worse in this aspect.

Is there a more elegant way?