"""Set initial values/limits in :class:`.DesignSpaceFactory`."""
import math
import numpy as np
from lightwin.core.elements.element import Element
[docs]
def same_value_as_nominal(
variable: str,
reference_element: Element,
**kwargs,
) -> float:
"""Return ``variable`` value in ``reference_element``.
This is generally a good initial value for optimisation.
"""
reference_value = reference_element.get(variable, to_numpy=False)
return reference_value
[docs]
def phi_s_limits(
reference_element: Element,
max_increase_sync_phase_in_percent: float,
max_absolute_sync_phase_in_deg: float = 0.0,
min_absolute_sync_phase_in_deg: float = -90.0,
**kwargs,
) -> tuple[float, float]:
r"""Return classic limits for the synchronous phase.
Minimum is ``min_absolute_sync_phase_in_deg``, which is -90 degrees by
default. Maximum is nominal synchronous phase +
``max_increase_in_percent``, or ``max_absolute_sync_phase_in_deg`` which is
0 degrees by default.
Parameters
----------
reference_element : Element
Element in its nominal tuning.
max_increase_in_percent : float
Maximum increase of the synchronous phase in percent.
max_absolute_sync_phase_in_deg : float, optional
Maximum absolute synchronous phase in radians. The default is 0.
min_absolute_sync_phase_in_deg : float, optional
Minimum absolute synchronous phase in radians. The default is
:math:`-\pi / 2`.
Returns
-------
tuple[float, float]
Lower and upper limits for the synchronous phase.
"""
reference_phi_s = same_value_as_nominal("phi_s", reference_element)
phi_s_min = math.radians(min_absolute_sync_phase_in_deg)
phi_s_max = min(
math.radians(max_absolute_sync_phase_in_deg),
reference_phi_s * (1.0 - 1e-2 * max_increase_sync_phase_in_percent),
)
return (phi_s_min, phi_s_max)
[docs]
def phi_0_limits(**kwargs) -> tuple[float, float]:
r"""Return classic limits for the absolute or relative rf phase.
Returns
-------
tuple[float, float]
Always :math:`(-2\pi, 2\pi)`.
"""
return (-2.0 * math.pi, 2.0 * math.pi)
[docs]
def k_e_limits(
reference_element: Element,
max_decrease_k_e_in_percent: float,
max_increase_k_e_in_percent: float,
maximum_k_e_is_calculated_wrt_maximum_k_e_of_section: bool = False,
reference_elements: list[Element] | None = None,
**kwargs,
) -> tuple[float, float]:
r"""Get classic limits for ``k_e``.
Parameters
----------
reference_element : Element
The nominal element.
max_decrease_in_percent : float
Allowed decrease in percent with respect to the nominal ``k_e``.
max_increase_in_percent : float
Allowed increase in percent with respect to the nominal ``k_e``.
maximum_k_e_is_calculated_wrt_maximum_k_e_of_section : bool, optional
Use this flag to compute allowed increase of ``k_e`` with respect to
the maximum ``k_e`` of the section, instead of the ``k_e`` of the
nominal cavity. This is what we used in :cite:`Placais2022a`. The
default is False.
reference_elements : list[Element] | None
List of the nominal elements. Must be provided if
``maximum_k_e_is_calculated_wrt_maximum_k_e_of_section`` is True.
Returns
-------
tuple[float, float]
Lower and upper bounds for ``k_e``.
"""
reference_k_e = same_value_as_nominal("k_e", reference_element)
min_k_e = reference_k_e * (1.0 - 1e-2 * max_decrease_k_e_in_percent)
max_k_e = reference_k_e * (1.0 + 1e-2 * max_increase_k_e_in_percent)
if not maximum_k_e_is_calculated_wrt_maximum_k_e_of_section:
return (min_k_e, max_k_e)
section_idx = reference_element.idx["section"]
assert reference_elements is not None
max_k_e_of_section = _get_maximum_k_e_of_section(
section_idx, reference_elements
)
max_k_e = max_k_e_of_section * (1.0 + 1e-2 * max_increase_k_e_in_percent)
return (min_k_e, max_k_e)
[docs]
def _get_maximum_k_e_of_section(
section_idx: int,
reference_elements: list[Element],
) -> float:
"""Get the maximum ``k_e`` of section."""
elements_in_current_section = list(
filter(
lambda element: element.idx["section"] == section_idx,
reference_elements,
)
)
k_e_in_current_section = [
element.get("k_e", to_numpy=False)
for element in elements_in_current_section
]
maximum_k_e = np.nanmax(k_e_in_current_section)
return maximum_k_e
LIMITS_CALCULATORS = {
"phi_s": phi_s_limits,
"phi_0_abs": phi_0_limits,
"phi_0_rel": phi_0_limits,
"k_e": k_e_limits,
}