Labview Optimizer Optimizers

I am trying to minimize a certain spectral coefficient with respect to a set of parameters participating in my array using global VI optimization and the process gets stuck. Maybe I'm using the wrong VI that I don't know. Here are screenshots of my code:

and sub-vi referenced by:

Basically it averages the array (whose values ​​are a linear function of three parameters) over one dimension, then obtains a certain coefficient of its energy spectrum, after which the main VI tries to minimize this coefficient over the three parameters mentioned above. Any ideas?