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oscillator_problem_engine.py
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Thu, Nov 28, 12:39

oscillator_problem_engine.py
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# Copyright (C) 2018 by the RROMPy authors
#
# This file is part of RROMPy.
#
# RROMPy is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# RROMPy 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 RROMPy. If not, see <http://www.gnu.org/licenses/>.
#
import numpy as np
import scipy.sparse as scsp
from numbers import Number
from rrompy.hfengines.base.linear_affine_engine import LinearAffineEngine
from rrompy.hfengines.base.scipy_engine_base import (ScipyEngineBase,
ScipyEngineBaseTensorized)
from rrompy.utilities.base.types import List, Np1D, Np2D
from rrompy.utilities.base import verbosityManager as vbMng
from rrompy.utilities.exception_manager import RROMPyAssert, RROMPyException
from rrompy.parameter import checkParameter
__all__ = ['OscillatorProblemEngine', 'AugmentedOscillatorProblemEngine']
class OscillatorProblemEngine(LinearAffineEngine, ScipyEngineBaseTensorized):
"""
Solver for damped mass oscillator problems.
Each i represents the factor in front of mu_i, except for i=0, which is a
constant. For each i:
(mass_i)_j = mass of j-th mass
(damping_i)_jk = damping between j-th and k-th mass
(stiffness_i)_jk = stiffness between j-th and k-th mass
Others:
input_ij = stiffness between i-th input and j-th mass
output_ij = contribution of j-th mass's position to i-th output
"""
def __init__(self, mass:List[Np1D], damping:List[Np2D],
stiffness:List[Np2D], input:Np2D, output:Np2D,
verbosity : int = 10, timestamp : bool = True):
super().__init__(verbosity = verbosity, timestamp = timestamp)
self._affinePoly = True
N, self.npar = len(mass[0]), len(mass)
RROMPyAssert(len(damping), self.npar, "Number of parameters")
RROMPyAssert(len(stiffness), self.npar, "Number of parameters")
input = np.array(input)
if input.ndim < 2: input = input.reshape(-1, 1)
self.nports = input.shape[1]
self.nAs, self.As, self.thAs = 3 * self.npar, [], []
self.nbs, self.bs = 1, [input.flatten()]
self._C = output
for j in range(self.npar):
deg = [0] * (self.npar - 1)
if j != 0: deg[j - 1] = 1
K = - stiffness[j]
Dj = - 1.j * damping[j]
if isinstance(Dj, (np.ndarray,)):
Mm = np.diag(- mass[j])
else:
Mm = scsp.diags([- mass[j]], [0], format = Dj.format)
for n in range(N):
K[n, n] = - np.sum(K[n])
if j == 0: K[n, n] += np.sum(input[n])
Dj[n, n] = - np.sum(Dj[n])
self.As += [K, Dj, Mm]
self.thAs += [self.getMonomialSingleWeight([0] + deg),
self.getMonomialSingleWeight([1] + deg),
self.getMonomialSingleWeight([2] + deg)]
if isinstance(self.As[0], (np.ndarray,)):
self.setSolver("SOLVE")
else:
self.setSolver("SPSOLVE", {"use_umfpack" : False})
class AugmentedOscillatorProblemEngine(OscillatorProblemEngine):
"""
Solver for damped mass oscillator problems.
Each i represents the factor in front of mu_i, except for i=0, which is a
constant. For each i:
(mass_i)_j = mass of j-th mass
(damping_i)_jk = damping between j-th and k-th mass
(stiffness_i)_jk = stiffness between j-th and k-th mass
Others:
input_ij = stiffness between i-th input and j-th mass
output_ij = contribution of j-th mass's position to i-th output
"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
N, self._nAs = self.As[0].shape[1], 2 * self.npar
self.bs = [np.pad(self.bs[0].reshape(-1, self.nports),
[(N, 0), (0, 0)], 'constant').flatten()]
if (not isinstance(self._C, (Number,))
and self._C.shape[1] != 2 * N):
RROMPyAssert(self._C.shape[1], N, "Shape of output")
self._C = np.pad(self._C, [(0, 0), (0, N)],
'constant')
As, thAs = [], []
for j in range(self.npar):
K, Dj, Mm = self.As[3 * j], self.As[3 * j + 1], self.As[3 * j + 2]
if isinstance(Dj, (np.ndarray,)):
I, Z = 1.j * np.eye(N), np.zeros((N, N))
Deff = np.block([[Z, - I], [K, Dj]])
Meff = np.block([[I, Z], [Z, Mm]])
else:
I = 1.j * scsp.eye(N)
Deff = scsp.bmat([[None, - I], [K, Dj]], format = Mm.format)
Meff = scsp.block_diag([I, Mm], format = Mm.format)
As += [Deff, Meff]
thAs += [self.thAs[3 * j], self.thAs[3 * j + 1]]
self.As, self.thAs = As, thAs
if isinstance(self.As[0], (np.ndarray,)):
self.setSolver("SOLVE")
else:
self.setSolver("SPSOLVE", {"use_umfpack" : False})

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