qat.interop.openqasm.OqasmParser

class qat.interop.openqasm.OqasmParser(gates: Optional[dict] = None, include_matrices: bool = True)

Parser of OpenQASM 2.0 files. This class provides tools to translate a string object (containing OpenQASM 2.0 source code) into a Circuit

Basic example

from qat.interop.openqasm import OqasmParser

# Define a dummy circuit
data = """
OPENQASM 2.0;

// Allocate qubits and cbits
qreg q[1];
creg c[1];

// Apply gates and measure
x q[0];
measure q[0] -> c[0];
"""

# Translate into a myQLM circuit
parser = OqasmParser()
circuit = parser.compile(data)
print("The circuit is composed of gates",
      list(circuit.iterate_simple()))

The circuit is composed of gates [('X', [], [0]), ('MEASURE', [0], [0])]

Advanced example

from qat.lang.AQASM import AbstractGate

# Define a circuit using OpenQASM
OPENQASM_CODE = """
OPENQASM 2.0;

// Allocating registers
qreg q[1];
creg c[1];

// Dummy circuit
p(pi/4) q[0];
my_custom_gate q[0];
"""

# Register gates (i.e. "p" gate is an alias for "PH" gate, "my_custom_gate" is defined by an abstract gate)
custom_gate = AbstractGate("custom_gate", [], arity)
parser = OqasmParser(gates={"p": "PH", "my_custom_gate": custom_gate}, include_matrices=False)

# Compile circuit and display it
for gate, angles, qubits in parser.compile(OQASM_CODE).iterate_simple():
    if angles:
        print(f"Apply {gate}{angles} on qubits {qubits}")
    else:
        print(f"Apply {gate} on qubits {qubits}")

Traceback (most recent call last):
  File "<stdin>", line 17, in <module>
NameError: name 'arity' is not defined

Parameters

• gates (dict[str, str or Gate], optional) – definition of custom gates. These gates are defined using a dictionary, a key corresponding to the OpenQASM gate identifier and the key being: - a str: the name of the equivalent gate in myQLM (e.g. “PH”, “X”, “U”, etc.) - a Gate: a custom gate

• include_matrices (bool, optional) – include matrices in the generated circuit (default: True)

compile(string, write_tables=False, debug=False, tabmodule='oqasm_tab', **kwargs)

Compiles a chunk of openqasm code sent as a parameter, and returns the corresponding QLM circuit

Parameters

• string – input openqasm code to parse

• debug – whether to activate debug output or not

• write_tables – generate parser table file or not (default False)

• tabmodule – parser tab to use (default oqasm_tab.py)

Returns

Corresponding QLM circuit