# Is there a defined minimal interface for a type to work with SparseArrays?

**URL:** <https://discourse.julialang.org/t/is-there-a-defined-minimal-interface-for-a-type-to-work-with-sparsearrays/69602>\
**Category:** Internals & Design\
**Tags:** sparse, interface\
**Created:** [October 12, 2021, 3:37am UTC](https://discourse.julialang.org/t/is-there-a-defined-minimal-interface-for-a-type-to-work-with-sparsearrays/69602 "2021-10-12T03:37:20Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![abraunst](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abraunst/32/6880_2.png) [@abraunst](https://discourse.julialang.org/u/abraunst)\
**Post date:** [October 21, 2021, 9:13am UTC](https://discourse.julialang.org/t/is-there-a-defined-minimal-interface-for-a-type-to-work-with-sparsearrays/69602/21 "2021-10-21T09:13:54Z")

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> [@suavesito](#):
>
> ```julia
> using Symbolics
> using SparseArrays
> 
> @variables a
> 
> v = sparsevec([1], [v])
> 
> v+v # here throws an error
> 
> ```

Now issue #42730

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**Author:** ![jlapeyre](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jlapeyre/32/4514_2.png) [@jlapeyre](https://discourse.julialang.org/u/jlapeyre)\
**Post date:** [October 21, 2021, 12:46pm UTC](https://discourse.julialang.org/t/is-there-a-defined-minimal-interface-for-a-type-to-work-with-sparsearrays/69602/22 "2021-10-21T12:46:07Z")

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Your example has a typo.

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<div class="post-metadata">

**Author:** ![abraunst](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abraunst/32/6880_2.png) [@abraunst](https://discourse.julialang.org/u/abraunst)\
**Post date:** [October 21, 2021, 1:05pm UTC](https://discourse.julialang.org/t/is-there-a-defined-minimal-interface-for-a-type-to-work-with-sparsearrays/69602/23 "2021-10-21T13:05:14Z")

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Not my example, but I had fixed in [https://github.com/JuliaLang/julia/issues/42730](https://github.com/JuliaLang/julia/issues/42730)

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