Circuit Simplifications
MIMIQ provides several tools to optimize and transform quantum circuits before execution. These tools help reduce circuit depth, remove unnecessary operations, and eliminate SWAP gates.
Cleaning Circuits
Remove Unused
The remove_unused function cleans up a circuit by removing unused qubits, classical bits, and Z-variables. This is useful when constructing circuits programmatically where some resources might be allocated but never used.
new_circuit, qubit_map, bit_map, zvar_map = remove_unused(circuit)Example:
c = Circuit()
push!(c, GateH(), 1) # Qubit 1 is used
push!(c, GateCX(), 1, 3) # Qubit 3 is used. Qubit 2 is unused.
new_c, qmap, bmap, zmap = remove_unused(c)
# new_c will have re-indexed qubits: 1->1, 3->2Remove SWAPs
The remove_swaps function is a powerful optimization that eliminates all SWAP gates from a circuit. Instead of executing physical swaps, it tracks the permutation of logical qubits and re-maps subsequent operations to the correct physical qubits.
new_circuit, final_permutation = remove_swaps(circuit; recursive=false)Example:
c = Circuit()
push!(c, GateH(), 1)
push!(c, GateSWAP(), 1, 2)
push!(c, GateCX(), 2, 3) # "Logical" qubit 2 is now at physical 1
new_c, perm = remove_swaps(c)
# new_c:
# H @ q[1]
# CX @ q[1], q[3] <-- Note: Target is physical 1 (was logial 2 pre-swap)