Moved quimb calls into a separate core function

src/qibotn/qasm_quimb.py

@@ -173,6 +173,18 @@ def qasm_QFT(nqubits: int, qasm_str: str, with_swaps: bool = True, psi0=None):
     return circ
 
 
+def tn_circ_eval(nqubits, qasm_circ, init_state, swaps=True, tn_lib="quimb",
+        backend='numpy'):
+    if tn_lib == "quimb":
+        circ_quimb = qasm_QFT(nqubits, qasm_circ, swaps, psi0=init_state)
+        interim = circ_quimb.psi.full_simplify(seq="DRC")
+        result = interim.to_dense(backend=backend).flatten()
+        return result
+    else:
+        # TODO: Change assert or value. Add cuquantum later
+        assert False, "Unsupported tensor network library"
+
+
 def eval_QI_qft(nqubits, backend="numpy", qibo_backend="qibojit", with_swaps=True):
     # backend (quimb): numpy, cupy, jax. Passed to ``opt_einsum``.
     # qibo_backend: qibojit, qibotf, tensorflow, numpy
@@ -197,17 +209,14 @@ def eval_QI_qft(nqubits, backend="numpy", qibo_backend="qibojit", with_swaps=Tru
     # Quimb circuit
     # convert vector to MPS
     dims = tuple(2 * np.ones(nqubits, dtype=int))
-    init_state_MPS = qtn.tensor_1d.MatrixProductState.from_dense(init_state_quimb, dims)
+    init_state_MPS = qtn.tensor_1d.MatrixProductState.from_dense(
+        init_state_quimb, dims)
 
     # construct quimb qft circuit
     start = timer()
-    circ_quimb = qasm_QFT(nqubits, qasm_circ, with_swaps, psi0=init_state_MPS)
-
-    interim = circ_quimb.psi.full_simplify(seq="DRC")
-
-    result = interim.to_dense(backend=backend)
-    amplitudes = result.flatten()
+    amplitudes = tn_circ_eval(nqubits=nqubits, qasm_circ=qasm_circ,
+                              init_state=init_state_MPS, swaps=with_swaps,
+                              tn_lib="quimb")
     end = timer()
     quimb_qft_time = end - start
-    print("quimb time is " + str(quimb_qft_time))
     assert np.allclose(amplitudes, amplitudes_reference, atol=1e-06)