forum.alglib.net

Make the following changes to your test code, place a breakpoint, and you'll see that function1_rep is never called.

void function1_rep(const real_1d_array &x, double func, void *ptr)
{
func = 0.0; // just to put breakpoint.
}

// alglib::minlbfgsoptimize(state, function1_func);
alglib::minlbfgsoptimize(state, function1_func, function1_rep);