# Error in DynamicPolynomials?

**URL:** <https://discourse.julialang.org/t/error-in-dynamicpolynomials/89196>\
**Category:** General Usage\
**Tags:** question, polynomials\
**Created:** [October 24, 2022, 4:24pm UTC](https://discourse.julialang.org/t/error-in-dynamicpolynomials/89196 "2022-10-24T16:24:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mhar](https://avatars.discourse-cdn.com/v4/letter/m/74df32/32.png) [@mhar](https://discourse.julialang.org/u/mhar)\
**Post date:** [October 24, 2022, 4:24pm UTC](https://discourse.julialang.org/t/error-in-dynamicpolynomials/89196/1 "2022-10-24T16:24:17Z")

</div>

The following code used to work, but I’m having an issue with it now:

```julia
using DynamicPolynomials
@polyvar var1 var2
v = randn(3);
_mons = monomials([var1, var2], length(v) - 1);
p = sum(_mons .* v)
p + p
ERROR: AssertionError: issorted(Z, lt = grlex)
Stacktrace:
 [1] MonomialVector{true}(vars::Vector{PolyVar{true}}, Z::Vector{Vector{Int64}})
   @ DynamicPolynomials ~/.julia/packages/DynamicPolynomials/jOoxo/src/monovec.jl:11
 [2] plusorminus(p::Polynomial{true, Float64}, q::Polynomial{true, Float64}, op::Function)
   @ DynamicPolynomials ~/.julia/packages/DynamicPolynomials/jOoxo/src/operators.jl:53
 [3] +(x::Polynomial{true, Float64}, y::Polynomial{true, Float64})
   @ DynamicPolynomials ~/.julia/packages/DynamicPolynomials/jOoxo/src/operators.jl:130
 [4] top-level scope
   @ REPL[33]:1

```

---

<div class="post-metadata">

**Author:** ![blegat](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/blegat/32/217090_2.png) [@blegat](https://discourse.julialang.org/u/blegat)\
**Post date:** [October 24, 2022, 4:31pm UTC](https://discourse.julialang.org/t/error-in-dynamicpolynomials/89196/2 "2022-10-24T16:31:56Z")

</div>

Can you check that you are not using the master branch of MultivariatePolynomials but rather the latest release ?  
This is due to the breaking change in [Reverse monomial order by blegat · Pull Request #225 · JuliaAlgebra/MultivariatePolynomials.jl · GitHub](https://github.com/JuliaAlgebra/MultivariatePolynomials.jl/pull/225) which needs [Update with MultivariatePolynomials#bl/term by blegat · Pull Request #113 · JuliaAlgebra/DynamicPolynomials.jl · GitHub](https://github.com/JuliaAlgebra/DynamicPolynomials.jl/pull/113).  
If you use the latest release of both packages, everything should be fine.  
I am waiting to be done with all the breaking changes I need to do for [gcd performance · Issue #194 · JuliaAlgebra/MultivariatePolynomials.jl · GitHub](https://github.com/JuliaAlgebra/MultivariatePolynomials.jl/issues/194) before making new releases. In the meantime, it’s best to stay way from the development branches and stay with releases.