Fix definition of _H to return 2H

pynkowski/data/so3data.py

@@ -341,15 +341,15 @@ def _V3(self, us, dus, verbose=True):
 
  @staticmethod
  def _H(first_der_t, second_der_t, psi):
- """Compute the mean curvature of the field at a given angle.
+ """Compute the mean curvature (times 2) of the field at a given angle.
  """
  first_der_t = first_der_t(psi)
  second_der_t = second_der_t(psi)
  hess = np.array([[second_der_t[0], second_der_t[3], second_der_t[4]],
  [second_der_t[3], second_der_t[1], second_der_t[5]],
  [second_der_t[4], second_der_t[5], second_der_t[2]]])
  norm_grad = first_der_t / np.sqrt(np.sum(first_der_t**2., axis=0))
- return np.einsum('j...,jk...,k... -> ...', norm_grad, hess, norm_grad) - np.trace(hess, axis1=0, axis2=1)
+ return 2.* (np.einsum('j...,jk...,k... -> ...', norm_grad, hess, norm_grad) - np.trace(hess, axis1=0, axis2=1))
 
  @staticmethod
  def _K(first_der_t, second_der_t, psi):