"""Hold mismatch related functions.
It has its own module as this quantity is pretty specific.
"""
import logging
import numpy as np
from lightwin.beam_calculation.simulation_output.simulation_output import (
SimulationOutput,
)
from lightwin.core.beam_parameters.helper import mismatch_from_arrays
from lightwin.core.elements.element import Element
from lightwin.optimisation.objective.objective import Objective
[docs]
class MinimizeMismatch(Objective):
"""Minimize a mismatch factor."""
[docs]
def __init__(
self,
name: str,
weight: float,
get_key: str,
get_kwargs: dict[str, Element | str | bool],
reference: SimulationOutput,
descriptor: str | None = None,
) -> None:
"""
Set complementary :meth:`.SimulationOutput.get` flags, reference value.
Parameters
----------
get_key : str
Must contain 'twiss' plus the name of a phase-space, or simply
'twiss' and the phase-space is defined in ``get_kwargs``.
get_kwargs : dict[str, Element | str | bool]
Keyword arguments for the :meth:`.SimulationOutput.get` method. We
do not check its validity, but in general you will want to define
the keys ``elt`` and ``pos``. You should also define the
``phase_space_name`` key if it is not defined in the ``get_key``.
reference : SimulationOutput
The reference simulation output from which the Twiss parameters
will be taken.
"""
if "twiss" not in get_key:
logging.warning(
"The get_key should contain 'twiss'. Taking 'twiss' and "
"setting phase space to zdelta."
)
get_key = "twiss"
get_kwargs["phase_space_name"] = "zdelta"
self.get_key = get_key
self.get_kwargs = get_kwargs
super().__init__(name, weight, descriptor=descriptor, ideal_value=0.0)
self._twiss_ref = self._twiss_getter(reference)
[docs]
def base_str(self) -> str:
"""Tell nature and position of objective."""
message = f"{self.name:>23}"
elt = str(self.get_kwargs.get("elt", "NA"))
message += f" @elt {elt:>5}"
pos = str(self.get_kwargs.get("pos", "NA"))
message += f" ({pos:>3}) | {self.weight:>5} | "
return message
[docs]
def __str__(self) -> str:
"""Give objective information value."""
return self.base_str() + f"{self.ideal_value:+.14e}"
[docs]
def _twiss_getter(self, simulation_output: SimulationOutput) -> np.ndarray:
"""Get desired value using :meth:`.SimulationOutput.get` method."""
return simulation_output.beam_parameters.get(
self.get_key, **self.get_kwargs
)
[docs]
def evaluate(self, simulation_output: SimulationOutput) -> float:
twiss_fix = self._twiss_getter(simulation_output)
return self._compute_residues(twiss_fix)
[docs]
def _compute_residues(self, twiss_fix: np.ndarray) -> float:
"""Compute the residues."""
res = mismatch_from_arrays(self._twiss_ref, twiss_fix)[0]
return self.weight * res