let x_L = [1.0, 1.0, 1.0, 1.0]
let x_U = [5.0, 5.0, 5.0, 5.0]
proc eval_f_12805296(n`gensym12805297: Index; x`gensym12805298: ptr Number;
                    new_x`gensym12805299: Bool;
                    obj_value`gensym12805300: ptr Number;
                    user_data`gensym12805301: UserDataPtr): Bool {.cdecl, exportc.} =
  result =
    ## Callback function for evaluating objective function
    let x = cast[ptr UncheckedArray[Number]](x`gensym12805298)
    obj_value`gensym12805300[] = x[0] * x[3] * (x[0] + x[1] + x[2]) + x[2]
    1