Types

quanta.core.types

quanta.core.types -- Core quantum types.

This module defines all fundamental data structures of the SDK

• QubitRef: Indexed reference to a qubit
• Instruction: Single circuit instruction (gate + qubits)
• QubitRegister: N-qubit register

These types are the foundation of the core layer with zero external dependencies.

Example

reg = QubitRegister(3) reg[0] QubitRef(index=0) len(reg) 3

CircuitError

Bases: QuantaError

Circuit creation or validation error.

Source code in quanta/core/types.py

class CircuitError(QuantaError):
    """Circuit creation or validation error."""

GateError

Bases: QuantaError

Gate definition or application error.

Source code in quanta/core/types.py

class GateError(QuantaError):
    """Gate definition or application error."""

Instruction dataclass

A single circuit instruction: gate + target qubits + parameters.

Created during circuit construction (lazy evaluation) and recorded into the CircuitBuilder.

Attributes:

Name	Type	Description
gate_name	str	Gate name (e.g., "H", "CX", "RY").
qubits	tuple[int, ...]	Target qubit indices.
params	tuple[float, ...]	Angle values for parametric gates (in radians).

Source code in quanta/core/types.py

@dataclass(frozen=True, slots=True)
class Instruction:
    """A single circuit instruction: gate + target qubits + parameters.

    Created during circuit construction (lazy evaluation)
    and recorded into the CircuitBuilder.

    Attributes:
        gate_name: Gate name (e.g., "H", "CX", "RY").
        qubits: Target qubit indices.
        params: Angle values for parametric gates (in radians).
    """

    gate_name: str
    qubits: tuple[int, ...]
    params: tuple[float, ...] = ()

MeasureSpec dataclass

Measurement specification: which qubits to measure.

Attributes:

Name	Type	Description
qubits	tuple[int, ...]	Qubit indices to measure. If empty, all are measured.

Source code in quanta/core/types.py

@dataclass(frozen=True, slots=True)
class MeasureSpec:
    """Measurement specification: which qubits to measure.

    Attributes:
        qubits: Qubit indices to measure. If empty, all are measured.
    """

    qubits: tuple[int, ...] = ()

QuantaError

Bases: Exception

Base error class for the Quanta SDK.

Source code in quanta/core/types.py

class QuantaError(Exception):
    """Base error class for the Quanta SDK."""

QubitIndexError

Bases: CircuitError

Invalid qubit index error.

Source code in quanta/core/types.py

class QubitIndexError(CircuitError):
    """Invalid qubit index error."""

QubitRef dataclass

Immutable reference to a qubit.

Created as q[0], q[1] within a circuit. Being frozen, it is hashable and can be used in sets/dicts.

Attributes:

Name	Type	Description
index	int	Zero-based index of the qubit within its register.

Source code in quanta/core/types.py

@dataclass(frozen=True, slots=True)
class QubitRef:
    """Immutable reference to a qubit.

    Created as `q[0]`, `q[1]` within a circuit.
    Being frozen, it is hashable and can be used in sets/dicts.

    Attributes:
        index: Zero-based index of the qubit within its register.
    """

    index: int

    def __repr__(self) -> str:
        return f"q[{self.index}]"

QubitRegister

An N-qubit register with indexed access.

Automatically created by @circuit(qubits=N). User accesses via q[0], q[1] or for qubit in q:.

Parameters:

Name	Type	Description	Default
size	int	Number of qubits. Must be a positive integer.	required

Raises:

Type	Description
CircuitError	If size < 1.

Example

reg = QubitRegister(3) reg[0], reg[1], reg[2] (q[0], q[1], q[2])

Source code in quanta/core/types.py

class QubitRegister:
    """An N-qubit register with indexed access.

    Automatically created by `@circuit(qubits=N)`.
    User accesses via `q[0]`, `q[1]` or `for qubit in q:`.

    Args:
        size: Number of qubits. Must be a positive integer.

    Raises:
        CircuitError: If size < 1.

    Example:
        >>> reg = QubitRegister(3)
        >>> reg[0], reg[1], reg[2]
        (q[0], q[1], q[2])
    """

    __slots__ = ("_size", "_qubits")

    def __init__(self, size: int) -> None:
        if size < 1:
            raise CircuitError(f"Qubit count must be positive, given: {size}")
        self._size = size
        self._qubits = tuple(QubitRef(i) for i in range(size))

    def __getitem__(self, index: int) -> QubitRef:
        """Access a single qubit. Supports negative indexing."""
        if index < -self._size or index >= self._size:
            raise QubitIndexError(
                f"Invalid qubit index. "
                f"Valid range: [0, {self._size - 1}]"
            )
        return self._qubits[index]

    def __iter__(self) -> Iterator[QubitRef]:
        """Iterate over all qubits."""
        return iter(self._qubits)

    def __len__(self) -> int:
        return self._size

    def __repr__(self) -> str:
        return f"QubitRegister(size={self._size})"

__getitem__

__getitem__(index: int) -> QubitRef

Access a single qubit. Supports negative indexing.

Source code in quanta/core/types.py

def __getitem__(self, index: int) -> QubitRef:
    """Access a single qubit. Supports negative indexing."""
    if index < -self._size or index >= self._size:
        raise QubitIndexError(
            f"Invalid qubit index. "
            f"Valid range: [0, {self._size - 1}]"
        )
    return self._qubits[index]

__iter__

__iter__() -> Iterator[QubitRef]

Iterate over all qubits.

Source code in quanta/core/types.py

def __iter__(self) -> Iterator[QubitRef]:
    """Iterate over all qubits."""
    return iter(self._qubits)

SimulatorError

Bases: QuantaError

Simulator execution error.

Source code in quanta/core/types.py

class SimulatorError(QuantaError):
    """Simulator execution error."""