# Copyright (C) 2024 qBraid
#
# This file is part of the qBraid-SDK
#
# The qBraid-SDK is free software released under the GNU General Public License v3
# or later. You can redistribute and/or modify it under the terms of the GPL v3.
# See the LICENSE file in the project root or <https://www.gnu.org/licenses/gpl-3.0.html>.
#
# THERE IS NO WARRANTY for the qBraid-SDK, as per Section 15 of the GPL v3.
"""
Module for defining custom conversions
"""
from __future__ import annotations
import importlib.util
import inspect
from typing import TYPE_CHECKING, Any, Callable, Optional, Union
import numpy as np
from qbraid.programs import QPROGRAM_REGISTRY, get_program_type_alias
if TYPE_CHECKING:
import qbraid.programs
[docs]
class Conversion:
"""
Class for defining and handling custom conversions between different quantum program packages.
"""
# pylint: disable-next=too-many-arguments
[docs]
def __init__(
self,
source: str,
target: str,
conversion_func: Callable,
weight: Optional[float] = None,
bias: Optional[float] = None,
):
"""
Initialize a Conversion instance with source and target packages and a conversion function.
Args:
source (str): The source package from which conversion starts.
target (str): The target package to which conversion is done.
conversion_func (Callable): The function that performs the actual conversion.
weight (Optional[float]): Optional weighting factor for the conversion, ranging [0,1].
If not specified, defaults to 1 or a custom value derived from the conversion_func.
bias (Optional[float]): Optional factor used to fine-tune the weight calculation and
modify the decision thresholds for pathfinding. Defaults to 0. Higher values
prioritize shorter paths. For example, a bias of 0.25 slightly favors a single
conversion at weight 0.8 over two conversions at weight 1.0, whereas a bias of 0.1
requires a single conversion of weight > 0.9 to be preferred over two at weight 1.0.
"""
self._source = source
self._target = target
self._conversion_func = conversion_func
self._bias = bias if bias is not None else 0
self._weight = self._get_adjusted_weight(weight)
self._extras = getattr(conversion_func, "requires_extras", [])
self._native = self._is_module_native(conversion_func)
self._supported = self._is_conversion_supported()
@property
def source(self) -> str:
"""
The source package of the conversion.
Returns:
str: The source package name.
"""
return self._source
@property
def target(self) -> str:
"""
The target package of the conversion.
Returns:
str: The target package name.
"""
return self._target
@property
def native(self) -> bool:
"""
True if the conversion function is native to qbraid package, False otherwise.
Returns:
bool: Whether the conversion function is native to qbraid package.
"""
return self._native
@property
def supported(self) -> bool:
"""
True if all packages required to perform the conversion are installed. False otherwise.
Returns:
bool: Whether the conversion function supported in the current runtime environment.
"""
return self._supported
@property
def weight(self) -> int:
"""
The weight of the conversion function used to prioritize conversion paths.
Returns:
int: The weight of the conversion function.
"""
return self._weight
def _get_adjusted_weight(self, weight: Optional[float] = None) -> float:
"""
Calculates and returns the effective weight of the conversion, applying a bias to
prioritize shorter conversion paths when used with pathfinding algorithms like rustworkx.
Args:
weight (float, optional): The initial weight provided by the user. Defaults to
the weight attribute of conversion_func if not provided.
Returns:
float: The calculated weight adjusted for pathfinding optimization.
Raises:
ValueError: If the calculated or provided weight is not between 0 and 1, inclusive.
"""
effective_weight = (
weight if weight is not None else getattr(self._conversion_func, "weight", 1)
)
if not 0 <= effective_weight <= 1:
raise ValueError("Weight must be a float between 0 and 1, inclusive.")
# Invert and log transform for positive weight differentiation with rustworkx
rx_adjusted_weight = float("inf") if effective_weight == 0 else np.log(1 / effective_weight)
adjusted_weight = rx_adjusted_weight + self._bias
return adjusted_weight
def _is_module_native(self, func: Callable) -> bool:
"""
Determine if the function's module is 'qbraid' and requires no extras.
Args:
func (Callable): The function to check the module of.
Returns:
bool: True if the module is 'qbraid' and requires no extras, False otherwise.
"""
module = inspect.getmodule(func)
is_native = (
module is not None
and module.__name__.split(".")[0] == "qbraid"
and len(self._extras) == 0
and getattr(func, "weight", None) is not None
)
return is_native
def _is_conversion_supported(self) -> bool:
"""
Determine if the required packages for the conversion are installed.
Returns:
bool: True if supported, otherwise False.
"""
if self._native:
return True
return all(importlib.util.find_spec(m) is not None for m in self._extras)
def convert(self, program: qbraid.programs.QPROGRAM) -> Union[qbraid.programs.QPROGRAM, Any]:
"""
Convert a quantum program from the source package to the target package.
Args:
program (qbraid.programs.QPROGRAM): The quantum program to be converted.
Returns:
Union[qbraid.programs.QPROGRAM, Any]: The converted quantum program,
typically of a supported program type.
Raises:
ValueError: If the provided program's type does not match the source package type.
"""
package = get_program_type_alias(program)
if package != self._source:
raise ValueError(
f"Expected program of type {QPROGRAM_REGISTRY[self._source]}, "
f"but got program of type {QPROGRAM_REGISTRY[package]}."
)
return self._conversion_func(program)
def __repr__(self) -> str:
"""
Represent the Conversion instance as a string indicating
source and target packages.
Returns:
str: String representation of the Conversion instance.
"""
return f"('{self._source}', '{self._target}')"
def __eq__(self, other: Any) -> bool:
"""
Check if another instance is equal to this instance.
Args:
other (Any): Another instance to compare.
Returns:
bool: True if the instances are equal, False otherwise.
"""
if not isinstance(other, Conversion):
return False
return (
self._source == other._source
and self._target == other._target
and self._native == other._native
and self._supported == other._supported
and self._extras == other._extras
and self._weight == other._weight
)