About gamultiobj "Undefined function or variable"

clear clc fitnessfcn = @ff_19; % Function handle to the fitness function nvars = 378; % Number of decision variables A= A; b= b; % No linear inequality constraints lb= lb; ub= ub; Aeq= Aeq; beq= beq; % No linear equality constraints options = gaoptimset('ParetoFraction',0.3,'PopulationSize',100,'Generations',200,'StallGenLimit',200,'TolFun',1e-100,'PlotFcns',@gaplotpareto); [x,fval] = gamultiobj(fitnessfcn,nvars, A,b,lb,ub,Aeq,beq,options);

??? Undefined function or variable 'A'.

Hi! Why the result is like this? Could you give me some suggestions? Thanks a lot.