# What's the proper way of dealing with Adjoint?
**URL:** https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457
**Category:** General Usage
**Tags:** question
**Created:** [August 14, 2018, 6:49pm UTC](https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457 "2018-08-14T18:49:58Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@vpetukhov](https://discourse.julialang.org/u/vpetukhov)
#### Post date: [August 14, 2018, 6:49pm UTC](https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457/1 "2018-08-14T18:49:58Z")
During upgrade of some libraries to Julia 0.7 I’ve met many situations where package developers use `DenseMatrix{T}` as an abstract class for a matrix data. But after new release, all code, which use `transpose` stopped working, as now it returns `Adjoint`, which is subtype of `AbstractArray{T,2}`. What is a proper way to upgrade such places?
Replacement of all `DenseMatrix{T}` with `AbstractArray{T,2}` would significantly increase class of accepted subtypes. Wrapping each occurrence of transposition (`m'`) with `Array(m')` looks too verbose as well as replacement of `DenseMatrix` with `Union{DenseMatrix, Adjoint}`.
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### Author:  [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)
#### Post date: [August 14, 2018, 7:14pm UTC](https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457/2 "2018-08-14T19:14:05Z")
`copy` to materialize the adjoint and it should work like before.
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### Author:  [@vpetukhov](https://discourse.julialang.org/u/vpetukhov)
#### Post date: [August 14, 2018, 8:14pm UTC](https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457/3 "2018-08-14T20:14:43Z")
Thanks for the reply!
Isn’t it as long as `Array(m')`? Do you really mean to use it each time with `'` operator?
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### Author:  [@carstenbauer](https://discourse.julialang.org/u/carstenbauer)
#### Post date: [August 14, 2018, 8:22pm UTC](https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457/4 "2018-08-14T20:22:50Z")
Before it was exactly doing this, creating a copy. So putting `copy` everywhere would kind of reproduce old behavior. However, by doing so, you might realize in some places why a lazy adjoint might be a better idea (performance wise).
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### Author:  [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)
#### Post date: [August 14, 2018, 8:22pm UTC](https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457/5 "2018-08-14T20:22:55Z")
You might not want to create an `Array`.
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### Author:  [@vpetukhov](https://discourse.julialang.org/u/vpetukhov)
#### Post date: [September 1, 2018, 1:25pm UTC](https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457/6 "2018-09-01T13:25:22Z")
Ok, got it, thank you!
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### Author:  [@DiracFermion1](https://discourse.julialang.org/u/DiracFermion1)
#### Post date: [August 23, 2021, 4:00pm UTC](https://discourse.julialang.org/t/whats-the-proper-way-of-dealing-with-adjoint/13457/7 "2021-08-23T16:00:37Z")
I am new to Julia, may I know what is the issue of creating an `Array` vs using `copy`?