# Why does not ibm-q-experience transpile a circuit always in the same way?

When I run a certain circuit (using several qubits, it is not a very simple one) in IBM quantum experience, I find that sometimes it is transpiled in one way and sometimes in another. And the final results are (quite) different. Specifically, I notice this fact in IBM q-computers with more than 5 qubits.

Is it possible to avoid this apparently random behaviour? Is it possible to control the way the circuit is transpiled?

• Hi and welcome to Quantum Computing SE. Different quantum processor have different physical implementation, or in other words they differ in connections among qubits (see for example physical implementation of Yorktown and Ourense). As a result, a circuit can be transpilled differently, mainly in terms of additional swap gates. – Martin Vesely Apr 1 '20 at 21:54

• If you use Qiskit you can make the behavior deterministic by passing a seed: transpiled_circuit = transpile(circuit, backend, seed_transpiler=2) – Ali Javadi Apr 1 '20 at 22:28