Simulation doesn't see variable when called inside a function

I have a simulation which has 5 parameters passed from workspace and I want to tune those parameters in order to minimize a fitness function. In a script I define initial values of those parameters and pass them to a function, where I run the simulation and calculate fitness value based on simulation's output. My function looks like this:

function [fitness_value] = fitness(consts)
out = sim('zad4');
water = out.water.data(length(out.water.data));
demand = out.demand.data(length(out.demand.data));
energy = out.energy.data(length(out.energy.data));
fitness_value = vpa(water, 16)/(vpa(demand, 16) * vpa(energy, 16) * 10^(-8))
end

The problem is when in main script I name the array of parameters as "consts_0" and call my function with this array, simulation doesn't see variable "consts". What should I change in order to run simulation with the parameters passed to a function?

Main script:

T_Z_open = 40;
E_on = 40.2;
E_off = 42;
partially_on = 40.5;
partially_off = 40;
consts_0 = [T_Z_open, E_on, E_off, partially_on, partially_off];

fitness(consts_0)
consts_min = fminsearch(@fitness, consts_0)

Error message:

Error using fitness (line 3)
Invalid setting in 'zad4/Constant' for parameter 'Value'.

Error in zad2 (line 15)
fitness(consts_0) - Show complete stack trace
Caused by:
    Error using fitness (line 3)
    Error evaluating parameter 'Value' in 'zad4/Constant' - Show complete
    stack trace
        Error using fitness (line 3)
        Unrecognized function or variable 'consts'. - Show complete stack
        trace
            Error using fitness (line 3)
            Variable 'consts' has been deleted from base workspace.
            Suggested Actions:
                • Undo the deletion. - Fix
                • Load a file into base workspace. - Fix
                • Create a new variable. - Fix
             - Show complete stack trace

Answer 1

[Fangjun Jiang]

The problem is that in your model, the block 'zad4/Constant' is looking for the parameter 'Value', presummabley from the base workspace.

There are a few approaches. The easiest thing to do is to add this line in your function before sim()

assignin('base','Value',consts);

[Rafal Ogorek]

Thank you, modifying your solution to assignin('base','consts',consts); worked.