iqm.qrisp_iqm.passes.routing.core.vf2pp.is_identity_embedding

iqm.qrisp_iqm.passes.routing.core.vf2pp.is_identity_embedding#

iqm.qrisp_iqm.passes.routing.core.vf2pp.is_identity_embedding(pattern_indices: ndarray, pattern_indptr: ndarray, target_indices: ndarray, target_indptr: ndarray) → bool#

Check whether the pattern graph is a subgraph of the target graph.

Tests the identity mapping, i.e. whether node i of the pattern graph can stay on node i of the target graph. For the layout passes this answers “does the circuit already have a valid layout?”, so circuit qubit i maps directly to physical qubit i.

Parameters:

  • pattern_indices (ndarray) – CSR neighbor indices of the circuit’s interaction graph, with one node per circuit qubit.

  • pattern_indptr (ndarray) – CSR index pointer of the circuit’s interaction graph.

  • target_indices (ndarray) – CSR neighbor indices of the target graph (device topology with one node per physical qubit). Neighbor lists must be sorted — the same requirement the VF2++ search makes.

  • target_indptr (ndarray) – CSR index pointer of the target graph.

Returns:

True if every edge of the pattern graph is also an edge of the target graph between the nodes of the same indices, False otherwise (including when the pattern graph has more nodes than the target graph).

Return type:

bool

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