"""
MDSuite: A Zincwarecode package.
License
-------
This program and the accompanying materials are made available under the terms
of the Eclipse Public License v2.0 which accompanies this distribution, and is
available at https://www.eclipse.org/legal/epl-v20.html
SPDX-License-Identifier: EPL-2.0
Copyright Contributors to the Zincwarecode Project.
Contact Information
-------------------
email: zincwarecode@gmail.com
github: https://github.com/zincware
web: https://zincwarecode.com/
Citation
--------
If you use this module please cite us with:
Summary
-------
Module for the computation of diffusion coefficients using the Green-Kubo approach.
"""
from abc import ABC
from dataclasses import dataclass
from typing import Any, List, Union
import numpy as np
import tensorflow as tf
import tensorflow_probability as tfp
from bokeh.models import HoverTool, LinearAxis, Span
from bokeh.models.ranges import Range1d
from bokeh.plotting import figure
from scipy.integrate import cumtrapz
from tqdm import tqdm
from mdsuite import utils
from mdsuite.calculators.calculator import call
from mdsuite.calculators.trajectory_calculator import TrajectoryCalculator
from mdsuite.database.mdsuite_properties import mdsuite_properties
[docs]@dataclass
class Args:
"""
Data class for the saved properties.
"""
data_range: int
correlation_time: int
atom_selection: np.s_
tau_values: np.s_
molecules: bool
species: list
integration_range: int
[docs]class GreenKuboDiffusionCoefficients(TrajectoryCalculator, ABC):
"""
Class for the Green-Kubo diffusion coefficient implementation
Attributes
----------
experiment : object
Experiment class to call from
species : list
Which species to perform the analysis on
x_label : str
X label of the tensor_values when plotted
y_label : str
Y label of the tensor_values when plotted
analysis_name : str
Name of the analysis
loaded_property : str
Property loaded from the database_path for the analysis
See Also
--------
mdsuite.calculators.calculator.Calculator class
Examples
--------
experiment.run_computation.GreenKuboSelfDiffusionCoefficients(data_range=500,
plot=True,
correlation_time=10)
"""
def __init__(self, **kwargs):
"""
Constructor for the Green Kubo diffusion coefficients class.
Attributes
----------
experiment : object
Experiment class to call from
"""
super().__init__(**kwargs)
self.loaded_property = mdsuite_properties.velocities
self.scale_function = {"linear": {"scale_factor": 150}}
self.x_label = r"$$\text{Time} / s$$"
self.y_label = r"$$\text{VACF} / m^{2}s^{-2}$$"
self.analysis_name = "Green Kubo Self-Diffusion Coefficients"
self.result_keys = ["diffusion_coefficient", "uncertainty"]
self.result_series_keys = ["time", "acf", "integral", "integral_uncertainty"]
self._dtype = tf.float64
@call
def __call__(
self,
plot: bool = True,
species: list = None,
data_range: int = 500,
correlation_time: int = 1,
atom_selection=np.s_[:],
molecules: bool = False,
tau_values: Union[int, List, Any] = np.s_[:],
integration_range: int = None,
):
"""
Constructor for the Green-Kubo diffusion coefficients class.
Parameters
----------
plot : bool
if true, plot the output.
species : list
List of species on which to operate.
data_range : int
Data range to use in the analysis.
correlation_time : int
Correlation time to use in the window sampling.
atom_selection : np.s_
Selection of atoms to use within the HDF5 database.
molecules : bool
If true, molecules are used instead of atoms.
integration_range : int
Range over which to integrate. Default is to integrate over
the full data range.
"""
if species is None:
if molecules:
species = list(self.experiment.molecules)
else:
species = list(self.experiment.species)
if integration_range is None:
integration_range = data_range - 1
# set args that will affect the computation result
self.args = Args(
data_range=data_range,
correlation_time=correlation_time,
atom_selection=atom_selection,
tau_values=tau_values,
molecules=molecules,
species=species,
integration_range=integration_range,
)
self.plot = plot
# Note: The following attributes are in SI units
self.time = self._handle_tau_values() * self.experiment.units.time
self.vacfs = []
self.sigmas = []
[docs] def ensemble_operation(self, ensemble):
"""
Calculate and return the msd.
Parameters
----------
ensemble
Returns
-------
MSD of the tensor_values.
"""
vacf = (
self.experiment.units.length**2
/ self.experiment.units.time**2
* tfp.stats.auto_correlation(ensemble, normalize=False, axis=1, center=False)
)
# average particles, sum dimensions
vacf = tf.reduce_sum(tf.reduce_mean(vacf, axis=0), -1)
self.sigmas.append(cumtrapz(vacf, x=self.time))
self.vacfs.append(vacf)
[docs] def plot_data(self, data: dict):
"""
Plot the data
Parameters
----------
data : dict
Data loaded from the sql database to be plotted.
"""
for selected_species, val in data.items():
fig = figure(x_axis_label=self.x_label, y_axis_label=self.y_label)
integral = np.array(val[self.result_series_keys[2]])
integral_err = np.array(val[self.result_series_keys[3]])
time = np.array(val[self.result_series_keys[0]])
vacf = np.array(val[self.result_series_keys[1]])
# Compute the span
span = Span(
location=np.array(val[self.result_series_keys[0]])[
self.args.integration_range - 1
],
dimension="height",
line_dash="dashed",
)
# Compute vacf line
fig.line(
time,
vacf,
color=utils.Colour.PRUSSIAN_BLUE,
legend_label=(
f"{selected_species}: {val[self.result_keys[0]][0]: 0.3E} +-"
f" {val[self.result_keys[1]][0]: 0.3E}"
),
)
fig.extra_y_ranges = {
"Diff_range": Range1d(start=0.6 * min(integral), end=1.3 * max(integral))
}
fig.add_layout(
LinearAxis(
y_range_name="Diff_range",
axis_label=r"$$\text{Diffusion Coefficient} / m^{2}s^{-1}$$",
),
"right",
)
fig.line(
time[1:], integral, y_range_name="Diff_range", color=utils.Colour.MULBERRY
)
fig.varea(
time[1:],
integral - integral_err,
integral + integral_err,
alpha=0.3,
color=utils.Colour.ORANGE,
y_range_name="Diff_range",
)
fig.add_tools(HoverTool())
fig.add_layout(span)
self.plot_array.append(fig)
[docs] def postprocessing(self, species: str):
"""
Apply post-processing to the data.
Parameters
----------
species : str
Current species on which you are operating.
Returns
-------
"""
self.sigmas = np.array(self.sigmas)
sigma = np.mean(self.sigmas, axis=0)
sigma_SEM = np.std(self.sigmas, axis=0) / np.sqrt(len(self.sigmas))
self.vacfs = np.array(self.vacfs)
vacf = np.mean(self.vacfs, axis=0)
diff_coeff = 1 / 3 * sigma[self.args.integration_range - 1]
diff_coeff_SEM = 1 / 3 * sigma_SEM[self.args.integration_range - 1]
data = {
self.result_keys[0]: [diff_coeff],
self.result_keys[1]: [diff_coeff_SEM],
self.result_series_keys[0]: self.time.tolist(),
self.result_series_keys[1]: vacf.tolist(),
self.result_series_keys[2]: sigma.tolist(),
self.result_series_keys[3]: sigma_SEM.tolist(),
}
self.queue_data(data=data, subjects=[species])
[docs] def run_calculator(self):
"""
Run analysis.
Returns
-------
"""
self.check_input()
# Loop over species
for species in self.args.species:
dict_ref = str.encode("/".join([species, self.loaded_property.name]))
batch_ds = self.get_batch_dataset([species])
for batch in tqdm(
batch_ds,
ncols=70,
desc=species,
total=self.n_batches,
disable=self.memory_manager.minibatch,
):
ensemble_ds = self.get_ensemble_dataset(batch, species)
for ensemble in ensemble_ds:
self.ensemble_operation(ensemble[dict_ref])
# Scale, save, and plot the data.
self.postprocessing(species)
self.sigmas = []
self.vacfs = []