Created an OrderTest class

This creates a testable framework so that we can easily test order of convergence on things like operators by just writing the guts of the code.

Merged Seogi's code into this framework.

SimPEG/tests/OrderTest.py

@@ -0,0 +1,50 @@
+import sys
+sys.path.append('../../')
+from SimPEG import TensorMesh
+import numpy as np
+import unittest
+
+
+class OrderTest(unittest.TestCase):
+    """Order test sets up the basics for testing order of decrease for a function on a mesh."""
+
+    name = "Order Test"
+    expectedOrder = 2
+    meshSizes = [4, 8, 16, 32]
+
+    def setupMesh(self, nc):
+        # Define the mesh
+        h1 = np.ones(nc)/nc
+        h2 = np.ones(nc)/nc
+        h3 = np.ones(nc)/nc
+        h = [h1, h2, h3]
+        self.M = TensorMesh(h)
+
+    def getError(self):
+        """Overwrite this function  with the guts of the test."""
+        return 1.
+
+    def orderTest(self):
+        order = []
+        err_old = 0.
+        nc_old = 0.
+        for ii, nc in enumerate(self.meshSizes):
+            self.setupMesh(nc)
+            err = self.getError()
+            if ii == 0:
+                print ''
+                print 'Testing order of:  ' + self.name
+                print '   h  |   inf norm  |  ratio   |  order'
+                print '------------------------------------------'
+                print '%4i  |  %8.2e   |' % (nc, err)
+            else:
+                order.append(np.log(err/err_old)/np.log(float(nc_old)/float(nc)))
+                print '%4i  |  %8.2e   |  %6.4f  |  %6.4f' % (nc, err, err_old/err, order[-1])
+            err_old = err
+            nc_old = nc
+
+        self.assertTrue(len(np.where(np.array(order) > 0.9*self.expectedOrder)[0]) > np.floor(0.75*len(order)))
+
+
+if __name__ == '__main__':
+    unittest.main()