Added a sub-module to utils to put analytics and source functions.

SimPEG/utils/Geophysics/__init__.py

@@ -0,0 +1 @@
+import emSources

SimPEG/utils/Geophysics/emSources/MagneticDipoleVectorPotential.py

@@ -0,0 +1,39 @@
+import numpy as np
+from scipy.constants import mu_0, pi
+
+def MagneticDipoleVectorPotential(txLoc, obsLoc, component, dipoleMoment=(0., 0., 1.)):
+    """
+        Calculate the vector potential of a set of magnetic dipoles
+        at given locations 'ref. <http://en.wikipedia.org/wiki/Dipole#Magnetic_vector_potential>'
+
+        :param numpy.ndarray txLoc: Location of the transmitter(s) (x, y, z)
+        :param numpy.ndarray obsLoc: Where the potentials will be calculated (x, y, z)
+        :param str component: The component to calculate - 'x', 'y', or 'z'
+        :param numpy.ndarray dipoleMoment: The vector dipole moment
+        :rtype: numpy.ndarray
+        :return: The vector potential each dipole at each observation location
+    """
+
+    if component=='x':
+        dimInd = 0
+    elif component=='y':
+        dimInd = 1
+    elif component=='z':
+        dimInd = 2
+    else:
+        raise ValueError('Invalid component')
+
+    txLoc = np.atleast_2d(txLoc)
+    obsLoc = np.atleast_2d(obsLoc)
+
+    nEdges = obsLoc.shape[0]
+    nTx = txLoc.shape[0]
+
+    m = np.array(dipoleMoment).repeat(nEdges, axis=0)
+    A = np.empty((nEdges, nTx))
+    for i in range(nTx):
+        dR = obsLoc - txLoc[i, np.newaxis].repeat(nEdges, axis=0)
+        mCr = np.cross(m, dR)
+        r = np.sqrt((dR**2).sum(axis=1))
+        A[:, i] = -(mu_0/(4*pi)) * mCr[:,dimInd]/(r**3)
+    return A

SimPEG/utils/Geophysics/emSources/__init__.py

@@ -0,0 +1 @@
+from MagneticDipoleVectorPotential import MagneticDipoleVectorPotential

SimPEG/utils/__init__.py

@@ -10,6 +10,7 @@ from interputils import interpmat
 from ipythonUtils import easyAnimate as animate
 import Solver
 from Solver import Solver
+import Geophysics
 
 def setKwargs(obj, **kwargs):
     """Sets key word arguments (kwargs) that are present in the object, throw an error if they don't exist."""