[dwpdwpdwpdwpdwp]

Mathematically, computation is deterministic. The author dismisses or ignores the many ways that the physical apparatus driving the computation can force the result of a software application to be a function of time.

Calling GetTimeOfDay() could do it.

Clock frequency drift between multiple processors could it.

[stevefan1999]

Quantum computer is under the category of computers.

Quantum computation relied on Quantum mechanics.

Quantum mechanics are not deterministic.

So, Quantum computers are not deterministic.

Therefore, unless P=NP, not all computations are deterministic.

[water9]

When theory fails to consult reality.