Fixes following phasespaceposition

Signed-off-by: nstarman <nstarman@users.noreply.github.com>

src/galdynamix/potential/_potential/base.py

@@ -89,7 +89,7 @@ def __call__(self, q: jt.Array, /, t: jt.Array) -> jt.Array:
         return self.potential_energy(q, t)
 
     @partial_jit()
-    def gradient(self, q: jt.Array, /, t: jt.Array) -> jt.Array: phasespaceposition
+    def gradient(self, q: jt.Array, /, t: jt.Array) -> jt.Array:
         """Compute the gradient of the potential at the given position(s).
 
         Parameters
@@ -127,14 +127,6 @@ def density(self, q: jt.Array, /, t: jt.Array) -> jt.Array:
             The potential energy or value of the potential.
         """
         lap = xp.trace(jax.hessian(self.potential_energy)(q, t))
-        """Compute the gradient."""
-        return jax.grad(self.potential_energy, argnums=0)(q, t)
-
-    @partial_jit()
-    def density(self, q: jt.Array, /, t: jt.Array) -> jt.Array:
-        # Note: trace(jacobian(gradient)) is faster than trace(hessian(energy))
-        lap = xp.trace(jax.jacfwd(self.gradient)(q, t))
-
         return lap / (4 * xp.pi * self._G)
 
     @partial_jit()