Source code for gemseo.problems.sobieski.core.mission

# 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 - initial API and implementation
#               and/or initial documentation
#        :author: Sobieski, Agte, and Sandusky
#    OTHER AUTHORS   - MACROSCOPIC CHANGES
#        :author: Damien Guenot
#        :author: Francois Gallard
# From NASA/TM-1998-208715
# Bi-Level Integrated System Synthesis (BLISS)
# Sobieski, Agte, and Sandusky
"""Mission discipline for the Sobieski's SSBJ use case."""
from __future__ import annotations

import logging

from numpy import array
from numpy import ndarray
from numpy import zeros

from gemseo.problems.sobieski.core.discipline import SobieskiDiscipline

LOGGER = logging.getLogger(__name__)


[docs]class SobieskiMission(SobieskiDiscipline): """Mission discipline for the Sobieski's SSBJ use case.""" @staticmethod def __compute_weight_ratio( w_t: float, w_f: float, ) -> float: """Compute the weight ratio from the Breguet formula. Args: w_t: The total weight. w_f: The fuel weight. Returns: The weight ratio ``w_t/(w_t-w_f)``. """ return w_t / (w_t - w_f) @staticmethod def __compute_dweightratio_dwt( w_t: float, w_f: float, ) -> float: """Derive the weight ratio with respect to the total weight. Args: w_t: The total aircraft weight. w_f: The fuel weight. Returns: The derivative of the weight ratio ``w_t/(w_t-w_f)`` with respect to the total weight. """ return -w_f / ((w_t - w_f) * (w_t - w_f)) @staticmethod def __compute_dweightratio_dwf( w_t: float, w_f: float, ) -> float: """Derive the weight ratio with respect to the fuel weight. Args: w_t: The total aircraft weight. w_f: The fuel weight. Returns: The derivative of the weight ratio ``w_t/(w_t-w_f)`` with respect to the fuel weight. """ return w_t / ((w_t - w_f) * (w_t - w_f)) def __compute_dlnweightratio_dwt( self, w_t: float, w_f: float, ) -> float: """Derive the logarithm of the weight ratio with respect to the total weight. Args: w_t: The total aircraft weight. w_f: The fuel weight. Returns: The derivative of the logarithm of the weight ratio ``w_t/(w_t-w_f)`` with respect to the total weight. """ return self.__compute_dweightratio_dwt(w_t, w_f) / self.__compute_weight_ratio( w_t, w_f ) def __compute_dlnweightratio_dwf( self, w_t: float, w_f: float, ) -> float: """Derive the logarithm of the weight ratio with respect to the fuel weight. Args: w_t: The total aircraft weight. w_f: The fuel weight. Returns: The derivative of the logarithm of the weight ratio ``w_t/(w_t-w_f)`` with respect to the fuel weight. """ return self.__compute_dweightratio_dwf(w_t, w_f) / self.__compute_weight_ratio( w_t, w_f ) def __compute_range( self, altitude: float, mach: float, w_t: float, w_f: float, cl_cd: float, sfc: float, ) -> float: """Compute the range from the Breguet formula. Args: altitude: The altitude. mach: The Mach number. w_t: The total aircraft weight. w_f: The fuel weight. cl_cd: The lift-over-drag ratio. sfc: The specific fuel consumption. Returns: The range. """ sqrt_theta = self.__compute_sqrt_theta(altitude) return ((mach * cl_cd) * 661.0 * sqrt_theta / sfc) * self.math.log( w_t / (w_t - w_f) ) def __compute_drange_dtotalweight( self, mach: float, w_t: float, w_f: float, cl_cd: float, sfc: float, sqrt_theta: float, ) -> float: """Derive the range with respect to the total weight. Args: mach: The Mach number. w_t: The total aircraft weight. w_f: The fuel weight. cl_cd: The lift-over-drag ratio. sfc: The specific fuel consumption. sqrt_theta: The square root of the air temperature. Returns: The derivative of the range with respect to the total weight. """ return ( mach * cl_cd / sfc * 661.0 * sqrt_theta * self.__compute_dlnweightratio_dwt(w_t, w_f) ) def __compute_drange_dfuelweight( self, mach: float, w_t: float, w_f: float, cl_cd: float, sfc: float, sqrt_theta: float, ) -> float: """Derive the range with respect to the fuel weight. Args: mach: The Mach number. w_t: The total aircraft weight. w_f: The fuel weight. cl_cd: The lift-over-drag ratio. sfc: The specific fuel consumption. sqrt_theta: The square root of the air temperature. Returns: The derivative of the range with respect to the fuel weight. """ return ( mach * cl_cd / sfc * 661.0 * sqrt_theta * self.__compute_dlnweightratio_dwf(w_t, w_f) ) def __compute_dtheta_dh(self, altitude: float) -> float: """Derive the square root of the air temperature wrt the altitude. Args: altitude: The altitude of the aircraft. Returns: The derivative of the square root of the air temperature wrt the altitude. """ if altitude < 36089.0: return -0.000006875 else: return 0.0 def __compute_sqrt_theta(self, altitude: float) -> float: """Compute the square root of the air temperature. Args: altitude: The altitude of the aircraft. Returns: The square root of the air temperature. """ if altitude < 36089.0: return self.math.sqrt(1 - 0.000006875 * altitude) else: return self.math.sqrt(0.7519)
[docs] def execute( self, x_shared: ndarray, y_14: ndarray, y_24: ndarray, y_34: ndarray, ) -> ndarray: """Compute the range. Args: x_shared: The shared design variables. y_14: The total aircraft weight ``y_14[0]`` and the fuel weight ``y_14[1]``. y_24: The lift-over-drag ratio. y_34: The specific fuel consumption. Returns: The range. """ return self._execute( x_shared[1], x_shared[2], y_14[0], y_14[1], y_24[0], y_34[0] )
def _execute( self, altitude: float, mach: float, w_t: float, w_f: float, cl_cd: float, sfc: float, ) -> ndarray: """Compute the range. Args: altitude: The altitude. mach: The Mach number. w_t: The total aircraft weight. w_f: The fuel weight. cl_cd: The lift-over-drag ratio. sfc: The specific fuel consumption. Returns: The range. """ return array( [self.__compute_range(altitude, mach, w_t, w_f, cl_cd, sfc)], dtype=self.dtype, ) def __initialize_jacobian(self) -> dict[str, dict[str, ndarray]]: """Initialize the Jacobian. Returns: The empty Jacobian. """ jacobian = {"y_4": {}} jacobian["y_4"]["x_shared"] = zeros((1, 6), dtype=self.dtype) jacobian["y_4"]["y_14"] = zeros((1, 2), dtype=self.dtype) jacobian["y_4"]["y_24"] = zeros((1, 1), dtype=self.dtype) jacobian["y_4"]["y_34"] = zeros((1, 1), dtype=self.dtype) return jacobian
[docs] def linearize( self, x_shared: ndarray, y_14: ndarray, y_24: ndarray, y_34: ndarray, ) -> dict[str, dict[str, ndarray]]: """Derive the discipline with respect to its inputs. Args: x_shared: The shared design variables. y_14: The total aircraft weight ``y_14[0]`` and the fuel weight ``y_14[1]``. y_24: The lift-over-drag ratio. y_34: The specific fuel consumption. Returns: The Jacobian of the discipline. """ return self._linearize( x_shared[1], x_shared[2], y_14[0], y_14[1], y_24[0], y_34[0] )
def _linearize( self, altitude: float, mach: float, w_t: float, w_f: float, cl_cd: float, sfc: float, ) -> dict[str, dict[str, ndarray]]: """Derive the discipline with respect to its inputs. Args: altitude: The altitude. mach: The Mach number. w_t: The total aircraft weight. w_f: The fuel weight. cl_cd: The lift-over-drag ratio. sfc: The specific fuel consumption. Returns: The Jacobian of the discipline. """ jacobian = self.__initialize_jacobian() sqrt_theta = self.__compute_sqrt_theta(altitude) dtheta_dh = self.__compute_dtheta_dh(altitude) ac_range = self.__compute_range(altitude, mach, w_t, w_f, cl_cd, sfc) # dR_d(h) jacobian["y_4"]["x_shared"][0, 1] = ( 0.5 * ac_range * dtheta_dh / (sqrt_theta * sqrt_theta) ) # dR_dM jacobian["y_4"]["x_shared"][0, 2] = ac_range / mach # dR_dWt jacobian["y_4"]["y_14"][0, 0] = self.__compute_drange_dtotalweight( mach, w_t, w_f, cl_cd, sfc, sqrt_theta ) # dR_dWf jacobian["y_4"]["y_14"][0, 1] = self.__compute_drange_dfuelweight( mach, w_t, w_f, cl_cd, sfc, sqrt_theta ) # dR_d(L/D) jacobian["y_4"]["y_24"][0, 0] = ac_range / cl_cd # dR_d(SFC) jacobian["y_4"]["y_34"][0, 0] = -ac_range / sfc return jacobian