Hello, I’m solving a linear optimization problem with JuMP (0.19.2) using GLPK.jl (0.10.0) as the solver. I’m struggling with the situation where the lower and upper bounds of a variable are equal (and because it’s in a vector of inequalities, I can’t just simply remove the variable). Here is a MWE…

So the issue is an ScalarAffineFunction-in-Interval constraint with identical bounds. There are multiple work-arounds: # Works model = Model(with_optimizer(GLPK.Optimizer)) @variable(model, x == 1) optimize!(model) # Works model = Model(with_optimizer(GLPK.Optimizer)) @variable(model, 1 <= x <= …

JuMP/GLPK with equal upper and lower bounds

Specific Domains Optimization (Mathematical)

odow September 9, 2019, 12:33pm 4

Explicit indexing is the way to go. The error message could be improved in the previous case. Want to open a GitHub issue at JuMP.jl?

You could also open an issue at GLPK.jl to remove direct support for interval constraints.

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JuMP/GLPK with equal upper and lower bounds

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