You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: VBA_evalFun.m
    path of file: ./repos/PsPM/src/ext/VBA
    
    the code of the file until where you have to start completion: function [fx,J,dfdP] = VBA_evalFun(flagFun,Xt,P,ut,options,dim,t)
% smart wrapper for evolution and observation functions
% function [fx,J,dfdP] = VBA_evalFun(flagFun,posterior,u,options,dim)
%
% This 
    
function [fx,dfdx,dfdp] = EvalFun(fname,Xt,P,ut,in,dim,nout,nout0,d)
% evaluates function, Jacobian and gradients (numerically if necessary)
dfdx = zeros(dim.n,dim.n);
dfdp = zeros(dim.n_theta,dim.n);
deriv = [1 1 1];
switch nout
    case 3
        [fx,dfdx,dfdp] = feval(fname,Xt,P,ut,in);
        if isempty(dfdx)
            deriv(1) = 0;
        end