Files
simpeg/code/TensorMesh.py
T

257 lines
9.4 KiB
Python

#-------------------------------------------------------------------------------
# Packages
#-------------------------------------------------------------------------------
import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
#-------------------------------------------------------------------------------
# Class definition
#-------------------------------------------------------------------------------
class TensorMesh:
"""
Define nodal, cell-centered and staggered tensor meshes for 1, 2 and 3
dimensions.
"""
# ---------------------- Properties --------------------------------------
h = None # Array Spacing or cell-sizes in each direction
x0 = None # Array Origin (x1,x2,x3)
dim = None # Int Dimension
n = None # Array Number of cells in each direction
nC = None # Int Total number of cells
nE = None # Int Total number of edges
nF = None # Int Total number of faces
# ----------------------- Methods ----------------------------------------
def __init__(self,h,x0):
"""Compute number of edges,faces and cell-centers """
# Assign values to properties
self.h = h
self.x0 = x0
#Compute derived properties
self.dim = np.size(x0)
#Compute the num of cells in each direction
self.n = np.zeros((self.dim,1))
for d in range(self.dim):
self.n[d] = np.size(h[d])
# Compute the number of cell-centers
self.nC = np.prod(self.n)
# Compute the number of edges (makes sense only for 3D)
# Equivalent to:
# nEdges = n[0] * (n[1]+1) * (n[2]+1)
# + (n[0]+1) * ny[1] * (nz[2]+1)
# + (n[0]+1) * (ny[1]+1)* (nz[2])
if self.dim == 3:
self.nE = np.prod(np.kron(np.ones((3,1)),self.n.T)+np.ones((3,3))-np.eye(3),1)
print self.nE
# Compute the number of faces (makes sense only for 2 and 3D)
# Equivalent to
# nFaces = (n[0]+1) * n[1] * n[2]
# + n[0] * (ny[1]+1) * nz[2]
# + n[0] * ny[1] * (nz[2]+1)
if self.dim >=2:
self.nF = np.prod(np.kron(np.ones((self.dim,1)),self.n.T)+np.eye(self.dim),1)
print self.nF
def xin(self,i):
"""Construct the 1D nodal mesh from the ith-component of h. Return an array."""
return np.insert(np.cumsum(self.h[i-1]),0,0.0) + self.x0[i-1]
def xic(self,i):
"""Construct the 1D cell-centerd mesh from the ith-component of h. Return an array."""
return .5*( np.insert(np.cumsum(self.h[i-1][:,0:-1]),0,0.0) + np.cumsum(self.h[i-1]))
def getNodalGrid(self):
"""Construct nodal grid for 1, 2 and 3 dimensions"""
if self.dim==1:
return [self.xin(1)]
elif self.dim==2:
return self.ndgrid([self.xin(1),self.xin(2)])
elif self.dim==3:
return self.ndgrid([self.xin(1),self.xin(2),self.xin(3)])
def ndgrid(self, xin):
"""Form tensorial grid for 1, 2 and 3 dimensions. Return X1,X2,X3 arrays depending on the dimension"""
ei = lambda i : np.ones((np.size(xin[i-1]),1))
if self.dim==1:
return [xin]
elif self.dim==2:
X1 = np.kron(ei(2),xin[0]).reshape(-1,1)
X2 = np.kron(xin[1],ei(1).T).reshape(-1,1)
return X1,X2
elif self.dim==3:
X1 = np.kron(ei(3),np.kron(ei(2),xin[0])).reshape(-1,1)
X2 = np.kron(ei(3).T,np.kron(xin[1],ei(1).T)).reshape(-1,1)
X3 = np.kron(xin[2],np.kron(ei(2),ei(1))).T.reshape(-1,1)
return X1,X2,X3
def getCellCenteredGrid(self):
"""Construct cell-centered grid for 1, 2 and 3 dimensions."""
if self.dim==1:
return [self.xic(1)]
elif self.dim==2:
return self.ndgrid([self.xic(1),self.xic(2)])
elif self.dim==3:
return self.ndgrid([self.xic(1),self.xic(2),self.xic(3)])
def getFaceStgGrid(self,direction):
"""Construct the face staggered grids for 2 and 3 dimensions."""
if self.dim==1:
print 'Error: dimension must be larger than 1'
elif self.dim==2:
if direction == 1:
return self.ndgrid([self.xin(1),self.xic(2)])
elif direction == 2:
return self.ndgrid([self.xic(1),self.xin(2)])
else:
print 'Error: direction must be equal to 1 or 2'
elif self.dim==3:
if direction == 1:
return self.ndgrid([self.xin(1),self.xic(2),self.xic(3)])
elif direction == 2:
return self.ndgrid([self.xic(1),self.xin(2),self.xic(3)])
elif direction == 3:
return self.ndgrid([self.xic(1),self.xic(2),self.xin(3)])
else:
print 'Error: direction must be equal to 1, 2 or 3'
def getEdgeStgGrid(self,direction):
"""Construct the edge staggered grids for 3 dimension case."""
if self.dim != 3:
print 'Error: dimension must be equal to 3'
else:
if direction == 1:
return self.ndgrid([self.xic(1),self.xin(2),self.xin(3)])
elif direction == 2:
return self.ndgrid([self.xin(1),self.xic(2),self.xin(3)])
elif direction == 3:
return self.ndgrid([self.xin(1),self.xin(2),self.xic(3)])
else:
print 'Error: direction must be equal to 1, 2 or 3'
def plotImage(self,I):
if self.dim==1:
fig = plt.figure(1)
fig.clf()
ax=plt.subplot(111)
if np.size(I)==self.n[0]:
print 'cell-centered image'
xx = self.getCellCenteredGrid()
ax.plot(xx[0],I,'ro')
elif np.size(I)==self.n[0]+1:
print 'nodal image'
xx = self.getNodalGrid()
ax.plot(xx[0],I,'bs')
fig.show()
def plotGrid(self):
"""Plot the nodal, cell-centered and staggered grids for 1,2 and 3 dimensions."""
if self.dim == 1:
fig = plt.figure(1)
fig.clf()
ax = plt.subplot(111)
xn = self.getNodalGrid()
xc = self.getCellCenteredGrid()
print xn
ax.hold(True)
ax.plot(xn,np.ones(np.shape(xn)),'bs')
ax.plot(xc,np.ones(np.shape(xc)),'ro')
ax.plot(xn,np.ones(np.shape(xn)),'k--')
ax.grid(True)
ax.hold(False)
ax.set_xlabel('x1')
fig.show()
elif self.dim == 2:
fig = plt.figure(2)
fig.clf()
ax = plt.subplot(111)
xn = self.getNodalGrid()
xc = self.getCellCenteredGrid()
xs1 = self.getFaceStgGrid(1)
xs2 = self.getFaceStgGrid(2)
ax.hold(True)
ax.plot(xn[0],xn[1],'bs')
ax.plot(xc[0],xc[1],'ro')
ax.plot(xs1[0],xs1[1],'g>')
ax.plot(xs2[0],xs2[1],'g^')
ax.grid(True)
ax.hold(False)
ax.set_xlabel('x1')
ax.set_ylabel('x2')
fig.show()
elif self.dim == 3:
fig = plt.figure(3)
fig.clf()
ax = fig.add_subplot(111, projection='3d')
xn = self.getNodalGrid()
xc = self.getCellCenteredGrid()
xfs1 = self.getFaceStgGrid(1)
xfs2 = self.getFaceStgGrid(2)
xfs3 = self.getFaceStgGrid(3)
xes1 = self.getEdgeStgGrid(1)
xes2 = self.getEdgeStgGrid(2)
xes3 = self.getEdgeStgGrid(3)
ax.hold(True)
ax.plot(xn[0],xn[1],'bs',zs=xn[2])
ax.plot(xc[0],xc[1],'ro',zs=xc[2])
ax.plot(xfs1[0],xfs1[1],'g>',zs=xfs1[2])
ax.plot(xfs2[0],xfs2[1],'g<',zs=xfs2[2])
ax.plot(xfs3[0],xfs3[1],'g^',zs=xfs3[2])
ax.plot(xes1[0],xes1[1],'k>',zs=xes1[2])
ax.plot(xes2[0],xes2[1],'k<',zs=xes2[2])
ax.plot(xes3[0],xes3[1],'k^',zs=xes3[2])
ax.grid(True)
ax.hold(False)
ax.set_xlabel('x1')
ax.set_ylabel('x2')
ax.set_zlabel('x3')
fig.show()
if __name__ == '__main__':
print('Welcome to tensor mesh!')
testDim = 1
h1 = 0.3*np.ones((1,7))
h1[:,0] = 0.5
h1[:,-1] = 0.6
h2 = .5* np.ones((1,4))
h3 = .4* np.ones((1,6))
x0 = np.zeros((3,1))
if testDim == 1:
h = [h1]
x0 = x0[0]
elif testDim==2:
h = [h1,h2]
x0 = x0[0:2]
else:
h = [h1,h2,h3]
I = np.linspace(0,1,8)
M = TensorMesh(h,x0)
xn = M.plotGrid()