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rational_moving_least_squares.py
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rational_moving_least_squares.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
import numpy as np
from .rational_interpolant import RationalInterpolant
from rrompy.utilities.poly_fitting.polynomial import (polybases as ppb,
polyvander as pvP,
polyvanderTotal as pvTP)
from rrompy.utilities.base.types import Np2D, HFEng, DictAny, paramVal
from rrompy.utilities.base import verbosityManager as vbMng
from rrompy.utilities.numerical import (fullDegreeMaxMask, totalDegreeMaxMask,
dot)
from rrompy.utilities.exception_manager import (RROMPyException, RROMPyAssert,
RROMPyWarning)
__all__ = ['RationalMovingLeastSquares']
class RationalMovingLeastSquares(RationalInterpolant):
"""
ROM rational moving LS interpolant 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;
- 'S': total number of samples current approximant relies upon;
- 'sampler': sample point generator;
- 'polybasis': type of polynomial basis for interpolation; defaults
to 'MONOMIAL';
- 'M': degree of rational interpolant numerator; defaults to 0;
- 'N': degree of rational interpolant denominator; defaults to 0;
- 'polydegreetype': type of polynomial degree; defaults to 'TOTAL';
- 'radialBasis': numerator radial basis type; defaults to
'GAUSSIAN';
- 'radialDirectionalWeights': radial basis weights for interpolant
numerator; defaults to 0, i.e. identity;
- 'nNearestNeighbor': number of nearest neighbors considered in
numerator if radialBasis allows; defaults to -1;
- 'radialBasisDen': denominator radial basis type; defaults to
'GAUSSIAN';
- 'radialDirectionalWeightsDen': radial basis weights for
interpolant denominator; defaults to 0, i.e. identity;
- 'nNearestNeighborDen': number of nearest neighbors considered in
denominator if radialBasisDen allows; defaults to -1;
- 'interpRcond': tolerance for interpolation; defaults to None;
- 'robustTol': tolerance for robust rational denominator
management; defaults to 0.
Defaults to empty dict.
approx_state(optional): Whether to approximate state. Defaults to
False.
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;
- 'polybasis': type of polynomial basis for interpolation;
- 'M': degree of rational interpolant numerator;
- 'N': degree of rational interpolant denominator;
- 'polydegreetype': type of polynomial degree;
- 'radialBasis': numerator radial basis type;
- 'radialDirectionalWeights': radial basis weights for interpolant
numerator;
- 'nNearestNeighbor': number of nearest neighbors considered in
numerator if radialBasis allows;
- 'radialBasisDen': denominator radial basis type;
- 'radialDirectionalWeightsDen': radial basis weights for
interpolant denominator;
- 'nNearestNeighborDen': number of nearest neighbors considered in
denominator if radialBasisDen allows;
- 'interpRcond': tolerance for interpolation via numpy.polyfit;
- 'robustTol': tolerance for robust rational denominator
management.
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.
S: Number of solution snapshots over which current approximant is
based upon.
sampler: Sample point generator.
polybasis: type of polynomial basis for interpolation.
M: Numerator degree of approximant.
N: Denominator degree of approximant.
polydegreetype: Type of polynomial degree.
radialBasis: Numerator radial basis type.
radialDirectionalWeights: Radial basis weights for interpolant
numerator.
nNearestNeighbor: Number of nearest neighbors considered in numerator
if radialBasis allows.
radialBasisDen: Denominator radial basis type.
radialDirectionalWeightsDen: Radial basis weights for interpolant
denominator.
nNearestNeighborDen: Number of nearest neighbors considered in
denominator if radialBasisDen allows.
interpRcond: Tolerance for interpolation via numpy.polyfit.
robustTol: Tolerance for robust rational denominator management.
muBounds: list of bounds for parameter values.
samplingEngine: Sampling engine.
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.
Q: Numpy 1D vector containing complex coefficients of approximant
denominator.
P: Numpy 2D vector whose columns are FE dofs of coefficients of
approximant numerator.
"""
def __init__(self, HFEngine:HFEng, mu0 : paramVal = None,
approxParameters : DictAny = {}, approx_state : bool = False,
verbosity : int = 10, timestamp : bool = True):
self._preInit()
self._addParametersToList(["radialBasis", "radialBasisDen",
"radialDirectionalWeightsDen",
"nNearestNeighborDen"],
["GAUSSIAN", "GAUSSIAN", 1, -1])
super().__init__(HFEngine = HFEngine, mu0 = mu0,
approxParameters = approxParameters,
approx_state = approx_state, verbosity = verbosity,
timestamp = timestamp)
self.catchInstability = False
self._postInit()
@property
def tModelType(self):
from rrompy.reduction_methods.trained_model import \
TrainedModelRationalMLS
return TrainedModelRationalMLS
@property
def polybasis(self):
"""Value of polybasis."""
return self._polybasis
@polybasis.setter
def polybasis(self, polybasis):
try:
polybasis = polybasis.upper().strip().replace(" ","")
if polybasis not in ppb:
raise RROMPyException("Prescribed polybasis not recognized.")
self._polybasis = polybasis
except:
RROMPyWarning(("Prescribed polybasis not recognized. Overriding "
"to 'MONOMIAL'."))
self._polybasis = "MONOMIAL"
self._approxParameters["polybasis"] = self.polybasis
@property
def radialBasis(self):
"""Value of radialBasis."""
return self._radialBasis
@radialBasis.setter
def radialBasis(self, radialBasis):
self._radialBasis = radialBasis
self._approxParameters["radialBasis"] = self.radialBasis
@property
def radialBasisDen(self):
"""Value of radialBasisDen."""
return self._radialBasisDen
@radialBasisDen.setter
def radialBasisDen(self, radialBasisDen):
self._radialBasisDen = radialBasisDen
self._approxParameters["radialBasisDen"] = self.radialBasisDen
@property
def radialDirectionalWeightsDen(self):
"""Value of radialDirectionalWeightsDen."""
return self._radialDirectionalWeightsDen
@radialDirectionalWeightsDen.setter
def radialDirectionalWeightsDen(self, radialDirectionalWeightsDen):
self._radialDirectionalWeightsDen = radialDirectionalWeightsDen
self._approxParameters["radialDirectionalWeightsDen"] = (
self.radialDirectionalWeightsDen)
@property
def nNearestNeighborDen(self):
"""Value of nNearestNeighborDen."""
return self._nNearestNeighborDen
@nNearestNeighborDen.setter
def nNearestNeighborDen(self, nNearestNeighborDen):
self._nNearestNeighborDen = nNearestNeighborDen
self._approxParameters["nNearestNeighborDen"] = (
self.nNearestNeighborDen)
def _setupDenominator(self) -> Np2D:
"""Compute rational denominator."""
RROMPyAssert(self._mode, message = "Cannot setup denominator.")
vbMng(self, "INIT",
"Starting computation of denominator-related blocks.", 7)
self._setupInterpolationIndices()
if self.polydegreetype == "TOTAL":
TN, _, argIdxs = pvTP(self._musUniqueCN, self.N, self.polybasis0,
self._derIdxs, self._reorder,
scl = np.power(self.scaleFactor, -1.))
TN = TN[:, argIdxs]
else: #if self.polydegreetype == "FULL":
TN = pvP(self._musUniqueCN, [self.N] * self.npar,
self.polybasis0, self._derIdxs, self._reorder,
scl = np.power(self.scaleFactor, -1.))
TNTen = np.zeros((self.S, self.S, TN.shape[1]), dtype = TN.dtype)
TNTen[np.arange(self.S), np.arange(self.S)] = TN
if self.POD: TNTen = dot(self.samplingEngine.RPOD, TNTen)
vbMng(self, "DEL", "Done computing denominator-related blocks.", 7)
return TN, TNTen
def _setupNumerator(self) -> Np2D:
"""Compute rational numerator."""
RROMPyAssert(self._mode, message = "Cannot setup numerator.")
vbMng(self, "INIT",
"Starting computation of denominator-related blocks.", 7)
self._setupInterpolationIndices()
if self.polydegreetype == "TOTAL":
TM, _, argIdxs = pvTP(self._musUniqueCN, self.M, self.polybasis0,
self._derIdxs, self._reorder,
scl = np.power(self.scaleFactor, -1.))
TM = TM[:, argIdxs]
else: #if self.polydegreetype == "FULL":
TM = pvP(self._musUniqueCN, [self.M] * self.npar,
self.polybasis0, self._derIdxs, self._reorder,
scl = np.power(self.scaleFactor, -1.))
vbMng(self, "DEL", "Done computing denominator-related blocks.", 7)
return TM
def setupApprox(self):
"""
Compute rational interpolant.
SVD-based robust eigenvalue management.
"""
if self.checkComputedApprox():
return
RROMPyAssert(self._mode, message = "Cannot setup approximant.")
vbMng(self, "INIT", "Setting up {}.". format(self.name()), 5)
self.computeSnapshots()
pMat = self.samplingEngine.samples.data
pMatEff = dot(self.HFEngine.C, pMat) if self.approx_state else pMat
if self.trainedModel is None:
self.trainedModel = self.tModelType()
self.trainedModel.verbosity = self.verbosity
self.trainedModel.timestamp = self.timestamp
datadict = {"mu0": self.mu0, "projMat": pMatEff,
"scaleFactor": self.scaleFactor,
"rescalingExp": self.HFEngine.rescalingExp}
data = self.initializeModelData(datadict)[0]
data.POD = self.POD
data.polybasis = self.polybasis
data.polydegreetype = self.polydegreetype
data.radialBasis = self.radialBasis
data.radialWeights = self.radialDirectionalWeights
data.nNearestNeighbor = self.nNearestNeighbor
data.radialBasisDen = self.radialBasisDen
data.radialWeightsDen = self.radialDirectionalWeightsDen
data.nNearestNeighborDen = self.nNearestNeighborDen
data.interpRcond = self.interpRcond
self.trainedModel.data = data
else:
self.trainedModel = self.trainedModel
self.trainedModel.data.projMat = copy(pMatEff)
if not self.POD:
self.trainedModel.data.gramian = self.HFEngine.innerProduct(
self.samplingEngine.samples,
self.samplingEngine.samples,
is_state = self.approx_state)
self.trainedModel.data.mus = copy(self.mus)
self.trainedModel.data.M = self.M
self.trainedModel.data.N = self.N
QVan, self.trainedModel.data.QBlocks = self._setupDenominator()
self.trainedModel.data.PVan = self._setupNumerator()
if self.polydegreetype == "TOTAL":
degreeMaxMask = totalDegreeMaxMask
else: #if self.polydegreetype == "FULL":
degreeMaxMask = fullDegreeMaxMask
if self.N > self.M:
self.trainedModel.data.QVan = QVan
self.trainedModel.data.domQIdxs = degreeMaxMask(self.N, self.npar)
else:
self.trainedModel.data.domQIdxs = degreeMaxMask(self.M, self.npar)
self.trainedModel.data.approxParameters = copy(self.approxParameters)
vbMng(self, "DEL", "Done setting up approximant.", 5)

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