The numerical simulations weren't accurate enough.

There are people who think that this universe is just an elaborate illusion, like a dream or computer simulation. "Māyā" is a Buddhist concept that relates to this mystical deception.

The proposed method is applied to three case studies in simulation.

By combining observations from MMS with new 3-D computer simulations, scientists have been able to investigate the small-scale physics of what’s happening at our magnetosphere’s borders for the first time.

The show is only a simulation of reality.

The numerical values shown above derive from Hobson's simulation.

This is only a simulation.

It's hard to explain, but you've been living in a simulation.

Are we living in a computer simulation?

I can speculate all I want about the nature of the universe and "reality," but such would be just speculation. I can say that our reality is like a computer simulation. I can say that our reality is like a hologram. I can say that our reality is like a dream. There are many more I-can-say's. They are speculations. As humans, we are like rabbits in that even if higher beings were to tell us the truth, we still might not understand.