# Array variable - matrix multplication in JuMP

**URL:** <https://discourse.julialang.org/t/array-variable-matrix-multplication-in-jump/49801>\
**Category:** Optimization (Mathematical)\
**Tags:** question, jump\
**Created:** [November 8, 2020, 7:57pm UTC](https://discourse.julialang.org/t/array-variable-matrix-multplication-in-jump/49801 "2020-11-08T19:57:02Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [November 8, 2020, 8:56pm UTC](https://discourse.julialang.org/t/array-variable-matrix-multplication-in-jump/49801/2 "2020-11-08T20:56:05Z")

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Hi there! Take a read of the first post in [Please read: make it easier to help you](https://discourse.julialang.org/t/psa-make-it-easier-to-help-you/14757). It explains how you can format your post, and why you should provide code instead of screenshots.

JuMP only supports matrix operators up to quadratic terms. It doesn’t support cubic.

My guess is you want something along the lines of:

```julia
model = Model()
@variable(model, 0 <= x[1:8, 1:8] <= 1)
@variable(model, y[1:8, 1:31])
@constraint(model, [t = 1:30], x * y[:, t] .== y[:, t + 1])

```

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