Simulation accuracy

I would like to ask about the accuracy that FreeFem++ can simulate?
Can the simulation accuracy reach 10^(-5)?

  1. What is accuracy?
  2. if you have good error estimator, yes.

This this your problem and it is not automatic.

Thanks for your reply. I am so happy.

My question is, if you want to simulate a real device, how much accuracy can be achieved by FreeFEM++.

For example, to simulate a cube, how much can its side length be accurate? (for example, 10 ^ (- 5) m)

Sorry, maybe I didn’t describe the problem clearly.