# Unsure what this error message means

**URL:** <https://discourse.julialang.org/t/unsure-what-this-error-message-means/88092>\
**Category:** New to Julia\
**Created:** [October 1, 2022, 5:50pm UTC](https://discourse.julialang.org/t/unsure-what-this-error-message-means/88092 "2022-10-01T17:50:23Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![bdas123](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bdas123/32/32142_2.png) [@bdas123](https://discourse.julialang.org/u/bdas123)\
**Post date:** [October 1, 2022, 5:50pm UTC](https://discourse.julialang.org/t/unsure-what-this-error-message-means/88092/1 "2022-10-01T17:50:24Z")

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Exception ‘MethodError: no method matching +(::Base.RefValue{Any}, ::NamedTuple{(:contents,), Tuple{Matrix{Float64}}})  
Closest candidates are:  
+(::Any, ::Any, !Matched::Any, !Matched::Any…) at operators.jl:560  
+(!Matched::Union{MathOptInterface.ScalarAffineFunction{T}, MathOptInterface.ScalarQuadraticFunction{T}}, ::T) where T at /home/ubuntu/.julia/packages/MathOptInterface/MMUy6/src/Utilities/functions.jl:1783  
+(!Matched::Union{InitialValues.NonspecificInitialValue, InitialValues.SpecificInitialValue{typeof(+)}}, ::Any) at /home/ubuntu/.julia/packages/InitialValues/OWP8V/src/InitialValues.jl:154  
…’ occurred while calling julia code:  
optimization(x0)

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<div class="post-metadata">

**Author:** ![longemen3000](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/longemen3000/32/7298_2.png) [@longemen3000](https://discourse.julialang.org/u/longemen3000)\
**Post date:** [October 1, 2022, 5:54pm UTC](https://discourse.julialang.org/t/unsure-what-this-error-message-means/88092/2 "2022-10-01T17:54:57Z")

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> [@bdas123](#):
>
> matching +(::Base.RefValue{Any}, ::NamedTuple{(:contents,), Tuple{Matrix{Float64}}})  
> Closest candidates are:  
> +(::Any, ::Any, !Matched::Any, !Matched::Any…) at operators.jl:560  
> +(!Matched::Union{MathOptInterface.ScalarAffineFunction{T}, MathOptInterface.ScalarQuadraticFunction{T}}, ::T) where T at /home/ubuntu/.julia/packages/MathOptInterface/MMUy6/src/Utilities/functions.jl:1783  
> +(!Matched::Union{InitialValues.NonspecificInitialValue, InitialValues.SpecificInitialValue{typeof(+)}}, ::Any) at /home/ubuntu/.julia/packages/InitialValues/OWP8V/src/InitialValues.jl:154  
> …’ occurred while calling julia code:  
> optimization(x0)

hmm, what code generated this error?

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<div class="post-metadata">

**Author:** ![digital\_carver](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/digital_carver/32/33818_2.png) [@digital\_carver](https://discourse.julialang.org/u/digital_carver)\
**Post date:** [October 1, 2022, 7:29pm UTC](https://discourse.julialang.org/t/unsure-what-this-error-message-means/88092/3 "2022-10-01T19:29:58Z")

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> [@bdas123](#):
>
> optimization(x0)

Is this `optimization` function from a package, or has it been defined somewhere else in your code? And what’s the value of `x0` here?

Showing us more of your code, and also pasting a more complete stacktrace of the error, will help a lot with figuring it out.