Instrument Model¶

We here introduce the InstrumentModel, which contains all information related to the instrument: the BackgroundModel, ResolutionModel and also a fittable offset in the energy transfer due to slight instrument misalignment.

The InstrumentModel does not itself do any calculations; it is merely a container for all information about the instrument.

In [1]:

import numpy as np

from easydynamics.sample_model import Gaussian
from easydynamics.sample_model import Polynomial
from easydynamics.sample_model.background_model import BackgroundModel
from easydynamics.sample_model.instrument_model import InstrumentModel
from easydynamics.sample_model.resolution_model import ResolutionModel

%matplotlib widget

import numpy as np from easydynamics.sample_model import Gaussian from easydynamics.sample_model import Polynomial from easydynamics.sample_model.background_model import BackgroundModel from easydynamics.sample_model.instrument_model import InstrumentModel from easydynamics.sample_model.resolution_model import ResolutionModel %matplotlib widget

In [2]:

# Create a BackgroundModel and a ResolutionModel and add them to an
# InstrumentModel

Q = np.linspace(0.1, 2.0, 5)

background_model = BackgroundModel()
background_model.components = Polynomial(coefficients=[1, 0.1, 0.01])

resolution_model = ResolutionModel()
resolution_model.append_component(Gaussian(width=0.05))

instrument_model = InstrumentModel(
    Q=Q,
    resolution_model=resolution_model,
    background_model=background_model,
)

# Create a BackgroundModel and a ResolutionModel and add them to an # InstrumentModel Q = np.linspace(0.1, 2.0, 5) background_model = BackgroundModel() background_model.components = Polynomial(coefficients=[1, 0.1, 0.01]) resolution_model = ResolutionModel() resolution_model.append_component(Gaussian(width=0.05)) instrument_model = InstrumentModel( Q=Q, resolution_model=resolution_model, background_model=background_model, )

In [3]:

instrument_model.get_all_variables(Q_index=1)

instrument_model.get_all_variables(Q_index=1)

Out[3]:

[<Parameter 'energy_offset': 0.0000 meV, bounds=[-inf:inf]>,
 <Parameter 'Polynomial_c0': 1.0000, bounds=[-inf:inf]>,
 <Parameter 'Polynomial_c1': 0.1000, bounds=[-inf:inf]>,
 <Parameter 'Polynomial_c2': 0.0100, bounds=[-inf:inf]>,
 <Parameter 'Gaussian area': 1.0000 meV, bounds=[0.0:inf]>,
 <Parameter 'Gaussian center': 0.0000 meV (fixed), bounds=[-inf:inf]>,
 <Parameter 'Gaussian width': 0.0500 meV, bounds=[1e-10:inf]>]

In [4]:

instrument_model.fix_resolution_parameters()
instrument_model.get_all_variables(Q_index=1)

instrument_model.fix_resolution_parameters() instrument_model.get_all_variables(Q_index=1)

Out[4]:

[<Parameter 'energy_offset': 0.0000 meV, bounds=[-inf:inf]>,
 <Parameter 'Polynomial_c0': 1.0000, bounds=[-inf:inf]>,
 <Parameter 'Polynomial_c1': 0.1000, bounds=[-inf:inf]>,
 <Parameter 'Polynomial_c2': 0.0100, bounds=[-inf:inf]>,
 <Parameter 'Gaussian area': 1.0000 meV (fixed), bounds=[0.0:inf]>,
 <Parameter 'Gaussian center': 0.0000 meV (fixed), bounds=[-inf:inf]>,
 <Parameter 'Gaussian width': 0.0500 meV (fixed), bounds=[1e-10:inf]>]