RelaxedNewton implemented, QuasiNewtonMinimizer has to be changed in _get_descent_direction

nifty/minimization/relaxed_newton.py

+# -*- coding: utf-8 -*-
+
+from .quasi_newton_minimizer import QuasiNewtonMinimizer
+
+
+class RelaxedNewton(QuasiNewtonMinimizer):
+    def _get_descend_direction(self, energy):
+        descend_direction = energy.curvature.inverse_times(energy.gradient)
+        norm = descend_direction.norm()
+        if norm != 1:
+            return descend_direction / -norm
+        else:
+            return descend_direction * -1