Numerical Error in Nonlinear Test

[DimitriAlston]

I believe there may be an issue here:

MathOptInterface.jl/src/Test/test_nonlinear.jl

Lines 1391 to 1400 in 2401296

	x1 in Interval(-2.001, 9.999)
	x2 in Interval(-2.001, 9.999)
	x3 in Interval(-2.001, 9.999)
	x4 in Interval(-2.001, 9.999)
	x5 in Interval(-2.001, 9.999)
	x6 in Interval(-2.001, 9.999)
	x7 in Interval(-2.001, 9.999)
	x8 in Interval(-2.001, 9.999)
	x9 in Interval(-2.001, 9.999)
	x10 in Interval(-2.001, 9.999)

The interval on each x should be Interval(2.001, 9.999) instead of Interval(-2.001, 9.999) for log(x - 2) to be defined.

Here's an example using Ipopt,

using JuMP, Ipopt
model = Model(Ipopt.Optimizer);

@variable(model, -2.001 <= x[1:10] <= 9.999);

f = log(x[1] - 2)^2 + log(10 - x[1])^2;
for i = 2:10
    f += log(x[i] - 2)^2 + log(10 - x[i])^2
end
f -= (x[1] * x[2] * x[3] * x[4] * x[5] * x[6] * x[7] * x[8] * x[9] * x[10])^0.2;

@objective(model, Min, f);

JuMP.optimize!(model)

which returns EXIT: Invalid number in NLP function or derivative detected.
If the variables are defined as @variable(model, 2.001 <= x[1:10] <= 9.999) instead, then the solution is found.

[odow]

It does look like it should be +2.001 😄