# Duality problem

**URL:** https://discourse.julialang.org/t/duality-problem/34045
**Category:** General Usage
**Created:** [January 31, 2020, 7:25pm UTC](https://discourse.julialang.org/t/duality-problem/34045 "2020-01-31T19:25:14Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![mahsap58](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mahsap58/32/11370_2.png) [@mahsap58](https://discourse.julialang.org/u/mahsap58)
#### Post date: [January 31, 2020, 7:25pm UTC](https://discourse.julialang.org/t/duality-problem/34045/1 "2020-01-31T19:25:14Z")

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Hi i am trying to use the ValueShapes package for getting the dual variables of my primal problem i faced this error  
Failed to precompile ValueShapes [136a8f8c-c49b-4edb-8b98-f3d64d48be8f]  
No deps.jl file could be found. Please try running Pkg.build(“Arpack”).  
Currently, the build command might fail when Julia has been built from source  
and the recommendation is to use the official binaries from [julialang.org](http://julialang.org).  
For more info see [https://github.com/JuliaLinearAlgebra/Arpack.jl/issues/5](https://github.com/JuliaLinearAlgebra/Arpack.jl/issues/5).