Files
simpeg/SimPEG/Mesh/CylMesh.py
T
2014-02-14 20:25:57 -08:00

376 lines
12 KiB
Python

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