@spec from_qasm(String.t()) :: {:ok, Qx.QuantumCircuit.t()} | {:error, Exception.t()}

Parses OpenQASM 3.0 source and returns a Qx.QuantumCircuit.

Round-trips with to_qasm/1: any program produced by to_qasm/1 parses back to a circuit that simulates to the same state vector.

Returns

• {:ok, %Qx.QuantumCircuit{}} on success
• {:error, %Qx.QasmParseError{}} on grammar/syntax failures
• {:error, %Qx.QasmUnsupportedError{}} for valid QASM that uses features Qx does not yet support (multi-register programs, gate modifiers, else branches, classical types beyond bit, …)
• {:error, %Qx.QubitIndexError{}} / {:error, %Qx.ClassicalBitError{}} for index validation failures

Examples

iex> qasm = ~s"""
...> OPENQASM 3.0;
...> include "stdgates.inc";
...> qubit[2] q;
...> bit[2] c;
...> h q[0];
...> cx q[0], q[1];
...> c[0] = measure q[0];
...> c[1] = measure q[1];
...> """
iex> {:ok, circuit} = Qx.Export.OpenQASM.from_qasm(qasm)
iex> circuit.num_qubits
2

Supported features

See the module doc for the supported gate set, decompositions, and the list of QASM 3 features deliberately excluded from v1 (each raises a typed Qx.QasmUnsupportedError).

@spec from_qasm!(String.t()) :: Qx.QuantumCircuit.t()

Like from_qasm/1 but raises on error.

@spec from_qasm_function(String.t()) :: {:ok, map()} | {:error, Exception.t()}

Parses an OpenQASM 3.0 program containing a gate definition and returns Elixir source code for an equivalent function.

The result map is %{name: String.t(), arity: pos_integer(), source: String.t()} where source is a def definition that can be inserted into a module via Code.compile_string/1 (or stored verbatim by callers like qxportal). The function takes (circuit, params..., qubits...) and returns the new circuit.

When the source contains multiple gate definitions, the last is treated as the "main" function — earlier ones are usually helpers which the main one references. Since user-defined gate references inside a gate body are rejected (Qx.QasmUnsupportedError), helpers themselves cannot be code-generated through this entry point.

If no gate definition is present, returns {:error, %Qx.QasmParseError{}}.

Example

iex> qasm = ~s"""
...> OPENQASM 3.0;
...> include "stdgates.inc";
...> gate bell a, b {
...>   h a;
...>   cx a, b;
...> }
...> """
iex> {:ok, %{name: "bell", arity: 3, source: source}} =
...>   Qx.Export.OpenQASM.from_qasm_function(qasm)
iex> source =~ "def bell(circuit, a, b)"
true

@spec from_qasm_function!(String.t()) :: map()

Like from_qasm_function/1 but raises on error.

Converts a Qx quantum circuit to OpenQASM format.

Parameters

• circuit - A Qx.QuantumCircuit struct
• options - Keyword list of options (default: [])

Options

• :version - OpenQASM version (2 or 3, default: 3)
• :include_comments - Add descriptive comments (default: false)
• :gate_style - Gate naming style (:standard or :verbose, default: :standard)

Returns

A string containing the OpenQASM program.

Raises

• Qx.GateError - If circuit contains unsupported gates
• Qx.ConditionalError - If circuit has conditionals but version is 2
• ArgumentError - If invalid options are provided

Examples

circuit = Qx.circuit(2) |> Qx.h(0) |> Qx.cnot(0, 1)
qasm = Qx.Export.OpenQASM.to_qasm(circuit)

# Output:
# OPENQASM 3.0;
# include "stdgates.inc";
#
# qubit[2] q;
# bit[2] c;
#
# h q[0];
# cx q[0], q[1];