How to re-order logical qubit location into desired state?

Question

Now, I'm studying about qubit mapping. When the mapping is done, the logical qubit will be randomly mapped to physical qubit. But I want to move the logical qubit location into desired state. For example, if the mapping state is like below. Left side is logical and right side is physical

1 -> 0
3 -> 1
2 -> 2
0 -> 3

So, after executing all quantum gates, I want the logical qubit's location would be like below

0
1
2
3

It means change the qubit state into desired state. (0, 1, 2, 3)

Or Is there any way(qiskit function) that I can extract the circuit's qubit location and change them?

Answer 1

I found something that could help you, it's a documentation with commands to do different operations between physical and virtual [qu]bits.

You could use something like this:

{(QuantumRegister(3, 'qr'), 0): 0,
 (QuantumRegister(3, 'qr'), 1): 1,
 (QuantumRegister(3, 'qr'), 2): 2}

Can be written more concisely as follows:

* virtual to physical::

    {qr[0]: 0,
     qr[1]: 1,
     qr[2]: 2}

* physical to virtual::

    {0: qr[0],
     1: qr[1],
     2: qr[2]}