"The fitness function should accept a row vector of length nvars and return a scalar value."
Your function, as defined, requires a row vector of length nvars and other information. For that scenario, see this suggestion in the Tips section on that documentation page:
"To write a function with additional parameters to the independent variables that can be called by ga, see Passing Extra Parameters (Optimization Toolbox)."
You will need to use one of the techniques on the Passing Extra Parameters page to pass additional inputs to your fitness function. The easiest will probably be the anonymous function approach.
