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reduced_basis_greedy.py
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reduced_basis_greedy.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/>.
#
from copy import deepcopy as copy
from .generic_greedy_approximant import GenericGreedyApproximant
from rrompy.reduction_methods.standard import ReducedBasis
from rrompy.utilities.base import verbosityManager as vbMng
from rrompy.utilities.exception_manager import RROMPyWarning, RROMPyAssert
__all__ = ['ReducedBasisGreedy']
class ReducedBasisGreedy(GenericGreedyApproximant, ReducedBasis):
"""
ROM greedy RB approximant computation for parametric problems.
Args:
HFEngine: HF problem solver.
mu0(optional): Default parameter. Defaults to 0.
approxParameters(optional): Dictionary containing values for main
parameters of approximant. Recognized keys are:
- 'POD': whether to compute POD of snapshots; defaults to True;
- 'scaleFactorDer': scaling factors for derivative computation;
defaults to 'AUTO';
- 'S': number of starting training points;
- 'sampler': sample point generator;
- 'greedyTol': uniform error tolerance for greedy algorithm;
defaults to 1e-2;
- 'collinearityTol': collinearity tolerance for greedy algorithm;
defaults to 0.;
- 'maxIter': maximum number of greedy steps; defaults to 1e2;
- 'nTestPoints': number of test points; defaults to 5e2;
- 'trainSetGenerator': training sample points generator; defaults
to sampler.
Defaults to empty dict.
approx_state(optional): Whether to approximate state. Defaults and must
be True.
verbosity(optional): Verbosity level. Defaults to 10.
Attributes:
HFEngine: HF problem solver.
mu0: Default parameter.
mus: Array of snapshot parameters.
approxParameters: Dictionary containing values for main parameters of
approximant. Recognized keys are in parameterList.
parameterListSoft: Recognized keys of soft approximant parameters:
- 'POD': whether to compute POD of snapshots;
- 'scaleFactorDer': scaling factors for derivative computation;
- 'greedyTol': uniform error tolerance for greedy algorithm;
- 'collinearityTol': collinearity tolerance for greedy algorithm;
- 'maxIter': maximum number of greedy steps;
- 'nTestPoints': number of test points;
- 'trainSetGenerator': training sample points generator.
parameterListCritical: Recognized keys of critical approximant
parameters:
- 'S': total number of samples current approximant relies upon;
- 'sampler': sample point generator.
approx_state: Whether to approximate state.
verbosity: Verbosity level.
POD: whether to compute POD of snapshots.
scaleFactorDer: Scaling factors for derivative computation.
S: number of test points.
sampler: Sample point generator.
greedyTol: uniform error tolerance for greedy algorithm.
collinearityTol: Collinearity tolerance for greedy algorithm.
maxIter: maximum number of greedy steps.
nTestPoints: number of starting training points.
trainSetGenerator: training sample points generator.
muBounds: list of bounds for parameter values.
samplingEngine: Sampling engine.
estimatorNormEngine: Engine for estimator norm computation.
uHF: High fidelity solution(s) with parameter(s) lastSolvedHF as
sampleList.
lastSolvedHF: Parameter(s) corresponding to last computed high fidelity
solution(s) as parameterList.
uApproxReduced: Reduced approximate solution(s) with parameter(s)
lastSolvedApprox as sampleList.
lastSolvedApproxReduced: Parameter(s) corresponding to last computed
reduced approximate solution(s) as parameterList.
uApprox: Approximate solution(s) with parameter(s) lastSolvedApprox as
sampleList.
lastSolvedApprox: Parameter(s) corresponding to last computed
approximate solution(s) as parameterList.
As: List of sparse matrices (in CSC format) representing coefficients
of linear system matrix.
bs: List of numpy vectors representing coefficients of linear system
RHS.
ARBs: List of sparse matrices (in CSC format) representing coefficients
of compressed linear system matrix.
bRBs: List of numpy vectors representing coefficients of compressed
linear system RHS.
"""
def __init__(self, *args, **kwargs):
self._preInit()
self._addParametersToList(toBeExcluded = ["R", "PODTolerance"])
super().__init__(*args, **kwargs)
self._postInit()
@property
def PODTolerance(self):
"""Value of PODTolerance."""
self._PODTolerance = -1
return self._PODTolerance
@PODTolerance.setter
def PODTolerance(self, PODTolerance):
RROMPyWarning(("PODTolerance is used just to simplify inheritance, "
"and its value cannot be changed from -1."))
def setupApproxLocal(self) -> int:
"""Compute RB projection matrix."""
if self.checkComputedApprox(): return -1
RROMPyAssert(self._mode, message = "Cannot setup approximant.")
self.verbosity -= 10
vbMng(self, "INIT", "Setting up local approximant.", 5)
vbMng(self, "INIT", "Computing projection matrix.", 7)
pMatOld, pMat = None, self.samplingEngine.samples.data
if self.trainedModel is not None:
Sold = len(self.trainedModel.data.mus)
pMatOld, pMat = pMat[:, : Sold], pMat[:, Sold :]
vbMng(self, "DEL", "Done computing projection matrix.", 7)
setData = self.trainedModel is None
self._setupTrainedModel(pMat, not setData)
if setData:
self.trainedModel.data.affinePoly = self.HFEngine.affinePoly
self.trainedModel.data.thAs = self.HFEngine.thAs
self.trainedModel.data.thbs = self.HFEngine.thbs
ARBs, bRBs = self.assembleReducedSystem(pMat, pMatOld)
self.trainedModel.data.ARBs = ARBs
self.trainedModel.data.bRBs = bRBs
self.trainedModel.data.approxParameters = copy(self.approxParameters)
vbMng(self, "DEL", "Done setting up local approximant.", 5)
self.verbosity += 10
return 0

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