add from_openqasm method

Author: refraction-ray

.gitignore

@@ -1,3 +1,4 @@
+data
 .prettierignore
 .idea/
 dataset

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 ## Unreleased
 
+### Added
+
+- Add native support for `rxx`, `ryy` and `rzz` gates for translation from qiskit
+
+- Add `from_openqasm` and `from_openqasm_file` methods for `Circuit`
+
+- Add `circuit_params` argument for translation from qiskit to make the interface universal and consistent with other `from_` methods
+
 ## 0.5.0
 
 ### Added

tensorcircuit/abstractcircuit.py

@@ -520,6 +520,26 @@ def to_openqasm(self, **kws: Any) -> str:
         """
         return self.to_qiskit().qasm(**kws)  # type: ignore
 
+    @classmethod
+    def from_openqasm(
+        cls, qasmstr: str, circuit_params: Optional[Dict[str, Any]] = None
+    ) -> "AbstractCircuit":
+        from qiskit.circuit import QuantumCircuit
+
+        qiskit_circ = QuantumCircuit.from_qasm_str(qasmstr)
+        c = cls.from_qiskit(qiskit_circ, circuit_params=circuit_params)
+        return c
+
+    @classmethod
+    def from_openqasm_file(
+        cls, file: str, circuit_params: Optional[Dict[str, Any]] = None
+    ) -> "AbstractCircuit":
+        from qiskit.circuit import QuantumCircuit
+
+        qiskit_circ = QuantumCircuit.from_qasm_file(file)
+        c = cls.from_qiskit(qiskit_circ, circuit_params=circuit_params)
+        return c
+
     def draw(self, **kws: Any) -> Any:
         """
         Visualise the circuit.
@@ -543,7 +563,11 @@ def draw(self, **kws: Any) -> Any:
 
     @classmethod
     def from_qiskit(
-        cls, qc: Any, n: Optional[int] = None, inputs: Optional[List[float]] = None
+        cls,
+        qc: Any,
+        n: Optional[int] = None,
+        inputs: Optional[List[float]] = None,
+        circuit_params: Optional[Dict[str, Any]] = None,
     ) -> "AbstractCircuit":
         """
         Import Qiskit QuantumCircuit object as a ``tc.Circuit`` object.
@@ -571,7 +595,7 @@ def from_qiskit(
         if n is None:
             n = qc.num_qubits
 
-        return qiskit2tc(qc.data, n, inputs, is_dm=cls.is_dm)  # type: ignore
+        return qiskit2tc(qc.data, n, inputs, is_dm=cls.is_dm, circuit_params=circuit_params)  # type: ignore
 
     def vis_tex(self, **kws: Any) -> str:
         """

tensorcircuit/translation.py

@@ -194,6 +194,7 @@ def qiskit2tc(
     n: int,
     inputs: Optional[List[float]] = None,
     is_dm: bool = False,
+    circuit_params: Optional[Dict[str, Any]] = None,
 ) -> Any:
     r"""
     Generate a tensorcircuit circuit using the quantum circuit data in qiskit.
@@ -220,10 +221,14 @@ def qiskit2tc(
         Circ = DMCircuit2
     else:
         Circ = Circuit  # type: ignore
-    if inputs is None:
-        tc_circuit: Any = Circ(n)
-    else:
-        tc_circuit = Circ(n, inputs=inputs)
+    if circuit_params is None:
+        circuit_params = {}
+    if "nqubits" not in circuit_params:
+        circuit_params["nqubits"] = n
+    if inputs is not None:
+        circuit_params["inputs"] = inputs
+
+    tc_circuit: Any = Circ(**circuit_params)
     for gate_info in qcdata:
         idx = [qb.index for qb in gate_info[1]]
         gate_name = gate_info[0].name
@@ -250,7 +255,7 @@ def qiskit2tc(
             getattr(tc_circuit, gate_name[:-1])(*idx)
         elif gate_name in ["cx_o0", "cy_o0", "cz_o0"]:
             getattr(tc_circuit, "o" + gate_name[1])(*idx)
-        elif gate_name in ["rx", "ry", "rz", "crx", "cry", "crz"]:
+        elif gate_name in ["rx", "ry", "rz", "crx", "cry", "crz", "rxx", "ryy", "rzz"]:
             getattr(tc_circuit, gate_name)(*idx, theta=parameters)
         elif gate_name in ["crx_o0", "cry_o0", "crz_o0"]:
             getattr(tc_circuit, "o" + gate_name[1:-3])(*idx, theta=parameters)

tests/test_circuit.py

@@ -976,6 +976,8 @@ def test_qiskit2tc():
     qisc.cz(0, 1, ctrl_state=0)
     qisc.cy(0, 1, ctrl_state=0)
     qisc.cx(0, 1, ctrl_state=0)
+    qisc.rxx(0.3, 1, 2)
+    qisc.rzz(-0.8, 2, 0)
     qisc.u(0.3, 0.9, -1.2, 2)
     qisc.rx(np.random.uniform(), 1)
     qisc.ry(np.random.uniform(), 2)
@@ -1219,4 +1221,12 @@ def test_to_openqasm():
     c.cnot(2, 1)
     c.rzz(0, 1, theta=-1.0)
     c.ccx(1, 2, 0)
+    c.u(2, theta=0.5, lbd=1.3)
     print(c.to_openqasm(formatted=True))
+    s = c.to_openqasm()
+    c1 = tc.Circuit.from_openqasm(s)
+    print(c1.draw())
+    np.testing.assert_allclose(c.state(), c1.state())
+    c.to_openqasm(filename="test.qasm")
+    c2 = tc.Circuit.from_openqasm_file("test.qasm")
+    np.testing.assert_allclose(c.state(), c2.state())