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376 lines
12 KiB
Python
376 lines
12 KiB
Python
import numpy as np
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import scipy.sparse as sp
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from scipy.constants import pi
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from SimPEG.Utils import mkvc, ndgrid, sdiag
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from TensorMesh import TensorMesh
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class CylMesh(TensorMesh):
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"""
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CylMesh is a mesh class for cylindrically problems
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"""
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_meshType = 'CYL'
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def __init__(self, h, x0=None):
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assert len(h) == 3, "len(h) must equal 3, for a cylindrically symmetric mesh use [hx, 1, hz]"
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if x0 is not None:
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assert x0.size == 3, "x0.size must equal 1"
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else:
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x0 = np.r_[0, 0, 0]
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for i, h_i in enumerate(h):
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if type(h_i) in [int, long, float]:
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# This gives you something over the unit cylinder.
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h_i = (2*np.pi if i==1 else 1.)*np.ones(int(h_i))/int(h_i)
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assert type(h_i) == np.ndarray, ("h[%i] is not a numpy array." % i)
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assert len(h_i.shape) == 1, ("h[%i] must be a 1D numpy array." % i)
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h[i] = h_i[:] # make a copy.
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assert h[1].sum() == 2*np.pi, "The 2nd dimension must sum to 2*pi"
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TensorMesh.__init__(self, h, x0)
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@property
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def nNx(self):
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"""
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Number of nodes in the x-direction
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:rtype: int
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:return: nNx
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"""
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return self.nCx
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@property
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def nNy(self):
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"""
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Number of nodes in the y-direction
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:rtype: int
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:return: nNy
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"""
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return self.nCy - 1
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@property
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def nN(self):
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"""
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Total number of nodes
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:rtype: int
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:return: nN
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"""
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return (np.r_[self.nNx, self.nNy, self.nNz]).prod()
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@property
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def nFx(self):
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"""
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Number of x-faces
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:rtype: int
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:return: nFx
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"""
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return self.nC
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@property
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def vnFx(self):
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"""
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Number of x-faces in each direction
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:rtype: numpy.array (dim, )
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:return: vnFx
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"""
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return self.vnC
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@property
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def nFy(self):
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"""
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Number of y-faces
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:rtype: int
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:return: nFy
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"""
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return (self.vnC + np.r_[0,-1,0][:self.dim]).prod()
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@property
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def nEx(self):
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"""
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Number of x-edges
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:rtype: int
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:return: nEx
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"""
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return (self._n + np.r_[0,-1,1]).prod()
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@property
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def nEy(self):
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"""
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Number of y-edges
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:rtype: int
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:return: nEy
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"""
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return (self._n + np.r_[0,0,1]).prod()
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@property
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def nEz(self):
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"""
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Number of z-edges
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:rtype: int
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:return: nEz
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"""
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return (self._n + np.r_[0,-1,0]).prod()
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@property
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def vectorNx(self):
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"""Nodal grid vector (1D) in the r direction"""
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return self.hr.cumsum()
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@property
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def edge(self):
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"""Edge lengths"""
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if getattr(self, '_edge', None) is None:
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self._edge = 2*pi*self.gridN[:,0]
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return self._edge
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@property
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def area(self):
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"""Face areas"""
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if getattr(self, '_area', None) is None:
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areaR = np.kron(self.hz, 2*pi*self.vectorNr)
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areaZ = np.kron(np.ones_like(self.vectorNz),pi*(self.vectorNr**2 - np.r_[0, self.vectorNr[:-1]]**2))
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self._area = np.r_[areaR, areaZ]
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return self._area
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@property
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def vol(self):
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"""Volume of each cell"""
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if getattr(self, '_vol', None) is None:
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az = pi*(self.vectorNr**2 - np.r_[0, self.vectorNr[:-1]]**2)
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self._vol = np.kron(self.hz,az)
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return self._vol
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####################################################
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# Operators
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####################################################
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@property
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def edgeCurl(self):
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"""The edgeCurl property."""
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if getattr(self, '_edgeCurl', None) is None:
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#1D Difference matricies
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dr = sp.spdiags((np.ones((self.nCx+1, 1))*[-1, 1]).T, [-1,0], self.nCx, self.nCx, format="csr")
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dz = sp.spdiags((np.ones((self.nCz+1, 1))*[-1, 1]).T, [0,1], self.nCz, self.nCz+1, format="csr")
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#2D Difference matricies
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Dr = sp.kron(sp.eye(self.nNz), dr)
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Dz = -sp.kron(dz, sp.eye(self.nCx)) #Not sure about this negative
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#Edge curl operator
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self._edgeCurl = sp.diags(1/self.area,0)*sp.vstack((Dz, Dr))*sp.diags(self.edge,0)
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return self._edgeCurl
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@property
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def aveE2CC(self):
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"""Averaging operator from cell edges to cell centres"""
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if getattr(self, '_aveE2CC', None) is None:
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az = sp.spdiags(0.5*np.ones((2, self.nNz)), [-1,0], self.nNz, self.nCz, format='csr')
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ar = sp.spdiags(0.5*np.ones((2, self.nCx)), [0, 1], self.nCx, self.nCx, format='csr')
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ar[0,0] = 1
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self._aveE2CC = sp.kron(az, ar).T
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return self._aveE2CC
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@property
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def aveF2CC(self):
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"""Averaging operator from cell faces to cell centres"""
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if getattr(self, '_aveF2CC', None) is None:
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az = sp.spdiags(0.5*np.ones((2, self.nNz)), [-1,0], self.nNz, self.nCz, format='csr')
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ar = sp.spdiags(0.5*np.ones((2, self.nCx)), [0, 1], self.nCx, self.nCx, format='csr')
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ar[0,0] = 1
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Afr = sp.kron(sp.eye(self.nCz),ar)
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Afz = sp.kron(az,sp.eye(self.nCx))
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self._aveF2CC = sp.vstack((Afr,Afz)).T
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return self._aveF2CC
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def getFaceMassDeriv(self):
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Av = self.aveF2CC
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return Av.T * sdiag(self.vol)
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def getEdgeMassDeriv(self):
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Av = self.aveE2CC
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return Av.T * sdiag(self.vol)
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####################################################
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# Methods
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####################################################
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def getMass(self, materialProp=None, loc='e'):
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""" Produces mass matricies.
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:param None,float,numpy.ndarray materialProp: property to be averaged (see below)
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:param str loc: Average to location: 'e'-edges, 'f'-faces
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:rtype: scipy.sparse.csr.csr_matrix
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:return: M, the mass matrix
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materialProp can be::
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None -> takes materialProp = 1 (default)
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float -> a constant value for entire domain
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numpy.ndarray -> if materialProp.size == self.nC
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3D property model
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if materialProp.size = self.nCz
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1D (layered eath) property model
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"""
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if materialProp is None:
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materialProp = np.ones(self.nC)
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elif type(materialProp) is float:
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materialProp = np.ones(self.nC)*materialProp
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elif materialProp.shape == (self.nCz,):
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materialProp = materialProp.repeat(self.nCx)
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materialProp = mkvc(materialProp)
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assert materialProp.shape == (self.nC,), "materialProp incorrect shape"
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if loc=='e':
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Av = self.aveE2CC
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elif loc=='f':
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Av = self.aveF2CC
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else:
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raise ValueError('Invalid loc')
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diag = Av.T * (self.vol * mkvc(materialProp))
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return sdiag(diag)
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def getEdgeMass(self, materialProp=None):
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"""mass matrix for products of edge functions w'*M(materialProp)*e"""
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return self.getMass(loc='e', materialProp=materialProp)
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def getFaceMass(self, materialProp=None):
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"""mass matrix for products of face functions w'*M(materialProp)*f"""
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return self.getMass(loc='f', materialProp=materialProp)
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def getInterpolationMat(self, loc, locType='fz'):
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""" Produces intrpolation matrix
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:param numpy.ndarray loc: Location of points to interpolate to
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:param str locType: What to interpolate (see below)
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:rtype: scipy.sparse.csr.csr_matrix
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:return: M, the intrpolation matrix
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locType can be::
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'fz' -> z-component of field defined on faces
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'fr' -> r-component of field defined on faces
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'et' -> theta-component of field defined on edges
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"""
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loc = np.atleast_2d(loc)
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assert np.all(loc[:,0]<=self.vectorNr.max()) & \
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np.all(loc[:,1]>=self.vectorNz.min()) & \
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np.all(loc[:,1]<=self.vectorNz.max()), \
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"Points outside of mesh"
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if locType=='fz':
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Q = sp.lil_matrix((loc.shape[0], self.nF), dtype=float)
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for i, iloc in enumerate(loc):
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# Point is on a z-interface
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if np.any(np.abs(self.vectorNz-iloc[1])<0.001):
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dFz = self.gridFz-iloc #Distance to z faces
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dFz[dFz[:,0]>0,:] = np.inf #Looking for next face to the left...
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indL = np.argmin(np.sum(dFz**2, axis=1)) #Closest one
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if self.gridFz[indL,0] == self.vectorCCr.max(): #Point in outer half cell (linear extrapolation)
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zFL = self.gridFz[indL,:]
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zFLL = self.gridFz[indL-1,:]
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Q[i, indL+self.nFr] = (iloc[0] - zFLL[0])/(zFL[0] - zFLL[0])
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Q[i, indL+self.nFr-1] = -(iloc[0] - zFL[0])/(zFL[0] - zFLL[0])
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else:
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zFL = self.gridFz[indL,:]
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zFR = self.gridFz[indL+1,:]
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Q[i,indL+self.nFr] = (zFR[0] - iloc[0])/(zFR[0] - zFL[0])
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Q[i,indL+self.nFr+1] = (iloc[0] - zFL[0])/(zFR[0] - zFL[0])
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# Point is in a cell
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else:
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dFz = self.gridFz-iloc
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dFz[dFz>0] = np.inf
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dFz = np.sum(dFz**2, axis=1)
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indBL = np.argmin(dFz) # Face below and to the left
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indAL = indBL + self.nCx # Face above and to the left
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zF_BL = self.gridFz[indBL,:]
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zF_AL = self.gridFz[indAL,:]
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dzB = iloc[1] - zF_BL[1] # z-distance to face below
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dzA = zF_AL[1] - iloc[1] # z-distance to face above
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if self.gridFz[indBL,0] == self.vectorCCr.max(): #Point in outer half cell (linear extrapolation)
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zF_BLL = self.gridFz[indBL-1,:]
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zF_ALL = self.gridFz[indAL-1,:]
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DZ = zF_AL[1] - zF_BL[1]
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DR = zF_AL[0] - zF_ALL[0]
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drL = iloc[0] - zF_AL[0]
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drLL = iloc[0] - zF_ALL[0]
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Q[i, indBL+self.nFr-1] = -(1 - dzB/DZ)*(drL/DR)
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Q[i, indBL+self.nFr] = (1 - dzB/DZ)*(drLL/DR)
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Q[i, indAL+self.nFr-1] = -(dzB/DZ)*(drL/DR)
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Q[i, indAL+self.nFr] = (dzB/DZ)*(drLL/DR)
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else:
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indBR = indBL+1 # Face below and to the right
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indAR = indAL + 1 # Face above and to the right
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zF_BR = self.gridFz[indBR,:]
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drL = iloc[0] - zF_BL[0] # r-distance to face on left
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drR = zF_BR[0] - iloc[0] # r-distance to face on right
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drz = (drL + drR)*(dzB + dzA)
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Q[i,indBL+self.nFr] = drR*dzA/drz
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Q[i,indBR+self.nFr] = drL*dzA/drz
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Q[i,indAL+self.nFr] = drR*dzB/drz
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Q[i,indAR+self.nFr] = drL*dzB/drz
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elif locType=='fr':
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raise NotImplementedError('locType==fr')
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elif locType=='et':
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raise NotImplementedError('locType==et')
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else:
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raise ValueError('Invalid locType')
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return Q.tocsr()
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def getNearest(self, loc, locType):
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""" Returns the index of the closest face or edge to a given location
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:param numpy.ndarray loc: Test point
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:param str locType: Type of location desired (see below)
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:rtype: int
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:return: ind:
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locType can be::
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'fz' -> location of nearest z-face
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'fr' -> location of nearest r-face
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'et' -> location of nearest edge
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"""
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if locType=='et':
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dr = self.gridN[:,0] - loc[0]
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dz = self.gridN[:,1] - loc[1]
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elif locType=='fz':
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dr = self.gridFz[:,0] - loc[0]
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dz = self.gridFz[:,1] - loc[1]
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elif locType=='fr':
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dr = self.gridFr[:,0] - loc[0]
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dz = self.gridFr[:,1] - loc[1]
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else:
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raise ValueError('Invalid locType')
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R = np.sqrt(dr**2 + dz**2)
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ind = np.argmin(R)
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return ind
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