# Copyright 2021 IRT Saint Exupéry, https://www.irt-saintexupery.com
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License version 3 as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
# Contributors:
# INITIAL AUTHORS - API and implementation and/or documentation
# :author: Francois Gallard
# :author: Damien Guenot
# OTHER AUTHORS - MACROSCOPIC CHANGES
"""Plot the derivatives of the functions."""
from __future__ import annotations
import logging
from typing import TYPE_CHECKING
from typing import ClassVar
from matplotlib import pyplot
from numpy import arange
from numpy import atleast_2d
from numpy import ndarray
from numpy import where
from gemseo.post.base_post import BasePost
from gemseo.post.gradient_sensitivity_settings import GradientSensitivity_Settings
from gemseo.utils.string_tools import repr_variable
if TYPE_CHECKING:
from collections.abc import Iterable
from matplotlib.figure import Figure
from gemseo.typing import NumberArray
from gemseo.typing import RealArray
LOGGER = logging.getLogger(__name__)
[docs]
class GradientSensitivity(BasePost[GradientSensitivity_Settings]):
"""Derivatives of the objective and constraints at a given iteration."""
Settings: ClassVar[type[GradientSensitivity_Settings]] = (
GradientSensitivity_Settings
)
def _plot(self, settings: GradientSensitivity_Settings) -> None:
compute_missing_gradients = settings.compute_missing_gradients
if settings.iteration is None:
design_value = self.optimization_problem.solution.x_opt
else:
design_value = self.optimization_problem.database.get_x_vect(
settings.iteration
)
fig = self.__generate_subplots(
self._get_design_variable_names(),
design_value,
self.__get_output_gradients(
design_value,
scale_gradients=settings.scale_gradients,
compute_missing_gradients=compute_missing_gradients,
),
settings.scale_gradients,
settings.fig_size,
)
fig.tight_layout()
self._add_figure(fig)
def __get_output_gradients(
self,
design_value: ndarray,
scale_gradients: bool = False,
compute_missing_gradients: bool = False,
) -> dict[str, RealArray]:
"""Return the gradients of all the output variable at a given design value.
Args:
design_value: The value of the design vector.
scale_gradients: Whether to normalize the gradients
w.r.t. the design variables.
compute_missing_gradients: Whether to compute the gradients at the
selected iteration if they were not computed by the algorithm.
.. warning::
Activating this option may add considerable computation time
depending on the cost of the gradient evaluation.
This option will not compute the gradients if the
:class:`.OptimizationProblem` instance was imported from an HDF5
file. This option requires an :class:`.OptimizationProblem` with a
gradient-based algorithm.
Returns:
The gradients of the outputs
indexed by the names of the output,
e.g. ``"output_name"`` for a mono-dimensional output,
or ``"output_name_i"`` for the i-th component of a multidimensional output.
"""
gradient_values = {}
if compute_missing_gradients:
try:
output_functions, jacobian_functions = (
self.optimization_problem.get_functions(
no_db_no_norm=True, jacobian_names=()
)
)
_, gradient_values = self.optimization_problem.evaluate_functions(
design_vector=design_value,
design_vector_is_normalized=False,
output_functions=output_functions or None,
jacobian_functions=jacobian_functions or None,
)
except NotImplementedError:
LOGGER.info(
"The missing gradients for an OptimizationProblem without "
"callable functions cannot be computed."
)
function_names = self.optimization_problem.function_names
scale_gradient = self.optimization_problem.design_space.unnormalize_vect
function_names_to_gradients = {}
for function_name in function_names:
if compute_missing_gradients and gradient_values:
gradient_value = gradient_values[function_name]
else:
gradient_value = self.database.get_function_value(
self.database.get_gradient_name(function_name), design_value
)
if gradient_value is None:
continue
gradient_value = atleast_2d(gradient_value)
size = len(gradient_value)
for i, _gradient_value in enumerate(gradient_value):
if scale_gradients:
_gradient_value = scale_gradient(_gradient_value, minus_lb=False)
function_names_to_gradients[repr_variable(function_name, i, size)] = (
_gradient_value
)
return function_names_to_gradients
def __generate_subplots(
self,
design_names: Iterable[str],
design_value: NumberArray,
gradients: dict[str, RealArray],
scale_gradients: bool,
fig_size: tuple[float, float],
) -> Figure:
"""Generate the gradients subplots from the data.
Args:
design_names: The names of the design variables.
design_value: The reference value for x.
gradients: The gradients to plot indexed by the output names.
scale_gradients: Whether to normalize the gradients
w.r.t. the design variables.
fig_size: The size of the figure.
Returns:
The gradients subplots.
Raises:
ValueError: If `gradients` is empty.
"""
n_gradients = len(gradients)
if n_gradients == 0:
msg = "No gradients to plot at current iteration."
raise ValueError(msg)
n_cols = 2
n_rows = sum(divmod(n_gradients, n_cols))
fig, axs = pyplot.subplots(
nrows=n_rows, ncols=n_cols, sharex=True, figsize=fig_size, squeeze=False
)
abscissa = arange(len(design_value))
if self._change_obj:
gradients[self._obj_name] = -gradients.pop(self._standardized_obj_name)
i = j = 0
font_size = 12
rotation = 90
for output_name, gradient_value in sorted(gradients.items()):
ax = axs[i][j]
ax.bar(
abscissa,
gradient_value,
color=where(gradient_value < 0, "blue", "red"),
align="center",
)
ax.grid()
ax.set_axisbelow(True)
ax.set_title(output_name)
ax.set_xticks(abscissa)
ax.set_xticklabels(design_names, fontsize=font_size, rotation=rotation)
# Update y labels spacing
vis_labels = [
label for label in ax.get_yticklabels() if label.get_visible() is True
]
pyplot.setp(vis_labels[::2], visible=False)
if j == n_cols - 1:
j = 0
i += 1
else:
j += 1
if j == n_cols - 1:
ax = axs[i][j]
ax.set_xticks(abscissa)
ax.set_xticklabels(design_names, fontsize=font_size, rotation=rotation)
title = (
"Derivatives of objective and constraints with respect to design variables"
)
if scale_gradients:
fig.suptitle(f"{title}\n\nNormalized design space.", fontsize=14)
else:
fig.suptitle(title, fontsize=14)
return fig
