"""Linear-probability quantum-like perception model."""
import numpy as np
from .angularmodel import AngularModel
from .model import Scalar
[docs]
class LinearModel(AngularModel):
"""Map a single normalized input linearly to measurement probability.
Warning
----------
For ``tau == 1``, measuring ``1`` has probability ``scalar_input``. A
constant input repeated over a longer window has the same relationship.
Time-varying windows accumulate inverse-sine rotation angles, so their
measurement probability is generally not the arithmetic mean of the inputs.
"""
[docs]
def encode(self, scalar_input: Scalar, dim: int) -> float:
"""Encode one scalar input using the linear-probability angle map.
Parameters
----------
scalar_input : float
Normalized input in the interval ``[0, 1]``.
dim : int
Zero-based input dimension.
Returns
-------
float
The rotation angle applied to the qubit.
"""
# Check the arguments
dim = self._dim_index_check(dim)
scalar_input = self._scalar_input_check(scalar_input)
# Apply rotation to the qubit
angle = (np.arcsin(2 * scalar_input - 1) + np.pi / 2) / self.tau
self.circ.ry(angle, dim)
return float(angle)