When simulating a quantum circuit using the
qasm_simulator, the qubits that you assign to the quantum circuit may be connected to all other qubits. In other words, if there are $n$ qubits in the quantum circuit, a single qubit can interact with all other $n-1$ qubits.
This is quite an unpractical hypothesis for real quantum computation. k-locality is a common criterion for a quantum computer and the only quantum computer I know of that has full qubit-connectivity is this one(I omitted the trivial cases of single- or two-qubit quantum computer). In the case of quantum devices that IBM provides via cloud access, e.g., 5-qubit ibmq_santiago, 5-qubit ibmq_5_yorktown, and 15-qubit ibmq_16_melbourne, all provide limited qubit connectivity.
So here arises my question: when designing a quantum circuit we have to take qubit connectivity into consideration, but how does
qiskit handle this? Does it assign the job automatically (such that the quantum circuit can still work), or should I pre-assign my logical qubits to the real qubits of the IBM quantum computer by hand? And if so, how do I do that?