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simpeg/SimPEG/tests/OrderTest.py
T

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Python

import sys
sys.path.append('../../')
from SimPEG import TensorMesh
import numpy as np
import unittest
class OrderTest(unittest.TestCase):
"""
OrderTest is a base class for testing convergence orders with respect to mesh
sizes of integral/differential operators.
Mathematical Problem:
Given are an operator A and its discretization A[h]. For a given test function f
and h --> 0 we compare:
error(h) = \| A[h](f) - A(f) \|_{\infty}
Note that you can provide any norm.
Test is passed when estimated rate order of convergence is at least within the specified tolerance of the
estimated rate supplied by the user.
Minimal example for a curl operator:
class TestCURL(OrderTest):
name = "Curl"
def getError(self):
# For given Mesh, generate A[h], f and A(f) and return norm of error.
fun = lambda x: np.cos(x) # i (cos(y)) + j (cos(z)) + k (cos(x))
sol = lambda x: np.sin(x) # i (sin(z)) + j (sin(x)) + k (sin(y))
Ex = fun(self.M.gridEx[:, 1])
Ey = fun(self.M.gridEy[:, 2])
Ez = fun(self.M.gridEz[:, 0])
f = np.concatenate((Ex, Ey, Ez))
Fx = sol(self.M.gridFx[:, 2])
Fy = sol(self.M.gridFy[:, 0])
Fz = sol(self.M.gridFz[:, 1])
Af = np.concatenate((Fx, Fy, Fz))
# Generate DIV matrix
Ah = self.M.edgeCurl
curlE = Ah*E
err = np.linalg.norm((Ah*f -Af), np.inf)
return err
def test_order(self):
# runs the test
self.orderTest()
See also: test_operatorOrder.py
"""
name = "Order Test"
expectedOrder = 2
tolerance = 0.85
meshSizes = [4, 8, 16, 32]
meshType = 'uniformTensorMesh'
meshDimension = 3
def setupMesh(self, nc):
"""
For a given number of cells nc, generate a TensorMesh with uniform cells with edge length h=1/nc.
"""
if 'TensorMesh' in self.meshType:
if 'uniform' in self.meshType:
h1 = np.ones(nc)/nc
h2 = np.ones(nc)/nc
h3 = np.ones(nc)/nc
h = [h1, h2, h3]
elif 'random' in self.meshType:
h1 = np.random.rand(nc)
h2 = np.random.rand(nc)
h3 = np.random.rand(nc)
h = [hi/np.sum(hi) for hi in [h1, h2, h3]] # normalize
else:
raise Exception('Unexpected meshType')
self.M = TensorMesh(h[:self.meshDimension])
max_h = max([np.max(hi) for hi in self.M.h])
return max_h
def getError(self):
"""For given h, generate A[h], f and A(f) and return norm of error."""
return 1.
def orderTest(self):
"""
For number of cells specified in meshSizes setup mesh, call getError
and prints mesh size, error, ratio between current and previous error,
and estimated order of convergence.
"""
order = []
err_old = 0.
max_h_old = 0.
for ii, nc in enumerate(self.meshSizes):
max_h = self.setupMesh(nc)
err = self.getError()
if ii == 0:
print ''
print 'Testing order of: ' + self.name
print '_____________________________________________'
print ' h | error | e(i-1)/e(i) | order'
print '~~~~~~|~~~~~~~~~~~~~|~~~~~~~~~~~~~|~~~~~~~~~~'
print '%4i | %8.2e |' % (nc, err)
else:
order.append(np.log(err/err_old)/np.log(max_h/max_h_old))
print '%4i | %8.2e | %6.4f | %6.4f' % (nc, err, err_old/err, order[-1])
err_old = err
max_h_old = max_h
print '---------------------------------------------'
passTest = np.mean(np.array(order)) > self.tolerance*self.expectedOrder
# passTest = len(np.where(np.array(order) > self.tolerance*self.expectedOrder)[0]) > np.floor(0.75*len(order))
self.assertTrue(passTest)
if __name__ == '__main__':
unittest.main()