Made get_tangent private.

grext/main.py

@@ -46,7 +46,7 @@ class Extrapolator:
         """Get a new electronic density to be used as a guess."""
         coefficients = fitting.linear()
 
-    def get_tangent(self) -> np.ndarray:
+    def _get_tangent(self) -> np.ndarray:
         """Get the tangent point."""
         if self.tangent is not None:
             return self.tangent
@@ -66,15 +66,13 @@ class Extrapolator:
 
     def _grassmann_log(self, coeff: np.ndarray) -> np.ndarray:
         """Map from the manifold to the tangent plane."""
-        if self.tangent is not None:
-            return grassmann.log(coeff, self.tangent)
-        raise ValueError("Tangent point is not set.")
+        tangent = self._get_tangent()
+        return grassmann.log(coeff, tangent)
 
     def _grassmann_exp(self, gamma: np.ndarray) -> np.ndarray:
         """Map from the tangent plane to the manifold."""
-        if self.tangent is not None:
-            return grassmann.exp(gamma, self.tangent)
-        raise ValueError("Tangent point is not set.")
+        tangent = self._get_tangent()
+        return grassmann.exp(gamma, tangent)
 
     def _sqrt_overlap(self, overlap):
         """Compute the square root of the overlap matrix."""

tests/test_grassmann.py

@@ -29,7 +29,7 @@ def test_grassmann_urea(datafile):
         extrapolator.load_data(coords, coeff, overlap)
 
     # check the Grassmann projections
-    c0 = extrapolator.get_tangent()
+    c0 = extrapolator._get_tangent()
     for (coeff, gamma, overlap) in zip(data["coefficients"],
             extrapolator.gammas.get(nframes), extrapolator.overlaps.get(nframes)):