[julia-users] help with bounds in NLopt

[Jude]

Hi,

In my model I iterate over a lot of different values and solve a 
constrained optimisation problem but for some values of my lower and upper 
bounds I get an error saying "invalid NLopt arguments". I am not sure why 
as my lower bound is < upper bound in all the iterations. I tried to 
understand this using a more simple example such as the following but even 
for this simple example if I set the bounds to (1,100) it's fine but if I 
use (2,100) I get the same error. Why is this?:

using NLopt
function simpleopt(lbA1, ubA1)

z=1

function test_max(x,z)
x[1]^2 + z 
end

count = 0 

function func(x::Vector, grad::Vector)
   global count +=1
    println("f_$count($x)")
 test_max(x[1],z)
end

opt = Opt(:LN_SBPLX,1)
lower_bounds!(opt, [lbA1])
upper_bounds!(opt, [ubA1])
min_objective!(opt, func)

(minf,minx,ret)=optimize(opt,[1])

println("got $minf at $minx after $count iterations (returned $ret)")
end