Creating orthogonality constraints in JuMP

[odow]

You want something like

for i = 1:n
    for j = i:n
        x_i = x[1:m, i]
        x_j = x[1:m, j]
        @NLconstraint(model, sumprod(xi..., xj...) == ((i==j) ? 1 : 0))
    end
end