Page MenuHomec4science
Files F60647643

helmholtz_square_bubble_domain_problem_engine.py
No OneTemporary
Actions

File Metadata

Created
Wed, May 1, 17:09

helmholtz_square_bubble_domain_problem_engine.py
View Options

# 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
import fenics as fen
from rrompy.utilities.base.types import Np1D, ScOp, Tuple, FenExpr, paramVal
from rrompy.solver.fenics import fenZERO
from .helmholtz_problem_engine import HelmholtzProblemEngine
from rrompy.utilities.base import verbosityDepth
from rrompy.parameter import parameter
__all__ = ['HelmholtzSquareBubbleDomainProblemEngine']
class HelmholtzSquareBubbleDomainProblemEngine(HelmholtzProblemEngine):
"""
Solver for square bubble Helmholtz problems with parametric domain heigth.
- \Delta u - kappa^2 * u = f in \Omega_mu = [0,\pi] x [0,\mu\pi]
u = 0 on \Gamma_mu = \partial\Omega_mu
with exact solution square bubble times plane wave.
"""
nAs, nbs = 3, 20
rescalingExp = 1.
def __init__(self, kappa:float, theta:float, n:int, mu0 : np.complex = 1.,
degree_threshold : int = np.inf, verbosity : int = 10,
timestamp : bool = True):
super().__init__(degree_threshold = degree_threshold,
verbosity = verbosity, timestamp = timestamp)
self.omega = kappa
self.kappa = kappa
self.theta = theta
self.mu0 = parameter(mu0)
self.forcingTermMu = np.nan
mesh = fen.RectangleMesh(fen.Point(0,0), fen.Point(np.pi,np.pi), n, n)
self.V = fen.FunctionSpace(mesh, "P", 3)
def buildEnergyNormForm(self): # H1
"""
Build sparse matrix (in CSR format) representative of scalar product.
"""
mudxM = np.abs(self.mu0(0)) * (fen.dot(self.u.dx(0), self.v.dx(0))
+ fen.dot(self.u, self.v))
imudy = 1. / np.abs(self.mu0(0)) * fen.dot(self.u.dx(1), self.v.dx(1))
normMatFen = fen.assemble((mudxM + imudy) * fen.dx)
normMat = fen.as_backend_type(normMatFen).mat()
self.energyNormMatrix = scsp.csr_matrix(normMat.getValuesCSR()[::-1],
shape = normMat.size)
def getForcingTerm(self, mu : paramVal = ()) -> Tuple[FenExpr, FenExpr]:
"""Compute forcing term."""
mu = self.checkParameter(mu)
if mu != self.forcingTermMu:
if self.verbosity >= 25:
verbosityDepth("INIT", ("Assembling base expression for "
"forcing term."),
timestamp = self.timestamp)
pi = np.pi
c, s = np.cos(self.theta), np.sin(self.theta)
x, y = fen.SpatialCoordinate(self.V.mesh())[:]
muR, muI = np.real(mu(0)), np.imag(mu(0))
mu2R, mu2I = np.real(mu(0) ** 2.), np.imag(mu(0) ** 2.)
C = 16. / pi ** 4.
bR = C * (2 * (x * (pi - x) + y * (pi - y))
+ (self.kappa * s) ** 2. * (mu2R - 1.)
* x * (pi - x) * y * (pi - y))
bI = C * (2 * self.kappa * (c * (pi - 2 * x) * y * (pi - y)
+ s * x * (pi - x) * (pi - 2 * y))
+ (self.kappa * s) ** 2. * mu2I
* x * (pi - x) * y * (pi - y))
wR = (fen.cos(self.kappa * (c * x + s * muR * y))
* fen.exp(self.kappa * s * muI * y))
wI = (fen.sin(self.kappa * (c * x + s * muR * y))
* fen.exp(self.kappa * s * muI * y))
self.forcingTerm = [bR * wR + bI * wI, bI * wR - bR * wI]
self.forcingTermMu = mu
if self.verbosity >= 25:
verbosityDepth("DEL", "Done assembling base expression.",
timestamp = self.timestamp)
return self.forcingTerm
def getExtraFactorB(self, mu : paramVal = (),
der : int = 0) -> Tuple[FenExpr, FenExpr]:
"""Compute extra expression in RHS."""
mu = self.checkParameter(mu)
def getPowMinusj(x, power):
powR = x ** power
powI = fenZERO
if power % 2 == 1:
powR, powI = powI, powR
if (power + 3) % 4 < 2:
powR, powI = - powR, - powI
return powR, powI
if self.verbosity >= 25:
verbosityDepth("INIT", ("Assembling auxiliary expression for "
"forcing term derivative."),
timestamp = self.timestamp)
from scipy.special import factorial as fact
y = fen.SpatialCoordinate(self.V.mesh())[1]
powR, powI = [(self.kappa * np.sin(self.theta)) ** der * k\
for k in getPowMinusj(y, der)]
mu2R, mu2I = np.real(mu(0) ** 2.), np.imag(mu(0) ** 2.)
exprR = mu2R * powR - mu2I * powI
exprI = mu2I * powR + mu2R * powI
if der >= 1:
muR, muI = np.real(2. * mu(0)), np.imag(2. * mu(0))
powR, powI = [(self.kappa * np.sin(self.theta)) ** (der - 1) * k\
* der for k in getPowMinusj(y, der - 1)]
exprR += muR * powR - muI * powI
exprI += muI * powR + muR * powI
if der >= 2:
powR, powI = [(self.kappa * np.sin(self.theta)) ** (der - 2) * k\
* der * (der - 1) for k in getPowMinusj(y, der - 2)]
exprR += powR
exprI += powI
fac = fact(der)
if self.verbosity >= 25:
verbosityDepth("DEL", "Done assembling auxiliary expression.",
timestamp = self.timestamp)
return [exprR / fac, exprI / fac]
def A(self, mu : paramVal = (), der : int = 0) -> ScOp:
"""Assemble (derivative of) operator of linear system."""
mu = self.checkParameter(mu)
Anull = self.checkAInBounds(der)
if Anull is not None: return Anull
self.autoSetDS()
if der <= 0 and self.As[0] is None:
if self.verbosity >= 20:
verbosityDepth("INIT", "Assembling operator term A0.",
timestamp = self.timestamp)
DirichletBC0 = fen.DirichletBC(self.V, fenZERO,
self.DirichletBoundary)
a0Re = fen.dot(self.u.dx(1), self.v.dx(1)) * fen.dx
A0Re = fen.assemble(a0Re)
DirichletBC0.apply(A0Re)
A0ReMat = fen.as_backend_type(A0Re).mat()
A0Rer, A0Rec, A0Rev = A0ReMat.getValuesCSR()
self.As[0] = scsp.csr_matrix((A0Rev, A0Rec, A0Rer),
shape = A0ReMat.size,
dtype = np.complex)
if self.verbosity >= 20:
verbosityDepth("DEL", "Done assembling operator term.",
timestamp = self.timestamp)
if der <= 2 and self.As[2] is None:
if self.verbosity >= 20:
verbosityDepth("INIT", "Assembling operator term A2.",
timestamp = self.timestamp)
DirichletBC0 = fen.DirichletBC(self.V, fenZERO,
self.DirichletBoundary)
nRe, nIm = self.refractionIndex
n2Re, n2Im = nRe * nRe - nIm * nIm, 2 * nRe * nIm
k2Re, k2Im = np.real(self.omega ** 2), np.imag(self.omega ** 2)
k2n2Re = k2Re * n2Re - k2Im * n2Im
k2n2Im = k2Re * n2Im + k2Im * n2Re
parsRe = self.iterReduceQuadratureDegree(zip([k2n2Re],
["kappaSquaredRefractionIndexSquaredReal"]))
parsIm = self.iterReduceQuadratureDegree(zip([k2n2Im],
["kappaSquaredRefractionIndexSquaredImag"]))
a2Re = (fen.dot(self.u.dx(0), self.v.dx(0))
- k2n2Re * fen.dot(self.u, self.v)) * fen.dx
a2Im = - k2n2Im * fen.dot(self.u, self.v) * fen.dx
A2Re = fen.assemble(a2Re, form_compiler_parameters = parsRe)
A2Im = fen.assemble(a2Im, form_compiler_parameters = parsIm)
DirichletBC0.zero(A2Re)
DirichletBC0.zero(A2Im)
A2ReMat = fen.as_backend_type(A2Re).mat()
A2ImMat = fen.as_backend_type(A2Im).mat()
A2Rer, A2Rec, A2Rev = A2ReMat.getValuesCSR()
A2Imr, A2Imc, A2Imv = A2ImMat.getValuesCSR()
self.As[2] = (scsp.csr_matrix((A2Rev, A2Rec, A2Rer),
shape = A2ReMat.size)
+ 1.j * scsp.csr_matrix((A2Imv, A2Imc, A2Imr),
shape = A2ImMat.size))
if self.verbosity >= 20:
verbosityDepth("DEL", "Done assembling operator term.",
timestamp = self.timestamp)
if der == 0:
return self.As[0] + mu(0) ** 2 * self.As[2]
if der == 1:
return 2. * mu(0) * self.As[2]
return self.As[2]
def b(self, mu : paramVal = (), der : int = 0,
homogeneized : bool = False) -> Np1D:
"""Assemble (derivative of) RHS of linear system."""
mu = self.checkParameter(mu)
bnull = self.checkbInBounds(der, homogeneized)
if bnull is not None: return bnull
if homogeneized and self.mu0BC != mu:
self.u0BC = self.liftDirichletData(mu)
if self.bsmu != mu:
self.bsmu = mu
self.resetbs()
b = self.bsH[der] if homogeneized else self.bs[der]
if b is None:
if self.verbosity >= 20:
verbosityDepth("INIT", ("Assembling forcing term "
"b{}.").format(der),
timestamp = self.timestamp)
if der < self.nbs:
fRe, fIm = self.getForcingTerm(mu)
cRe, cIm = self.getExtraFactorB(mu, der)
cfRe = cRe * fRe - cIm * fIm
cfIm = cRe * fIm + cIm * fRe
else:
cfRe, cfIm = fenZERO, fenZERO
parsRe = self.iterReduceQuadratureDegree(zip([cfRe],
["forcingTermDer{}Real".format(der)]))
parsIm = self.iterReduceQuadratureDegree(zip([cfIm],
["forcingTermDer{}Imag".format(der)]))
L0Re = fen.dot(cfRe, self.v) * fen.dx
L0Im = fen.dot(cfIm, self.v) * fen.dx
b0Re = fen.assemble(L0Re, form_compiler_parameters = parsRe)
b0Im = fen.assemble(L0Im, form_compiler_parameters = parsIm)
if homogeneized:
Ader = self.A(mu, der)
b0Re[:] -= np.real(Ader.dot(self.u0BC))
b0Im[:] -= np.imag(Ader.dot(self.u0BC))
DirichletBC0 = fen.DirichletBC(self.V, fenZERO,
self.DirichletBoundary)
DirichletBC0.apply(b0Re)
DirichletBC0.apply(b0Im)
b = np.array(b0Re[:] + 1.j * b0Im[:], dtype = np.complex)
if homogeneized:
self.bsH[der] = b
else:
self.bs[der] = b
if self.verbosity >= 20:
verbosityDepth("DEL", "Done assembling forcing term.",
timestamp = self.timestamp)
return b

Event Timeline

c4science · Help