Revert Morgan's changes to the split criteria

Author: v715

sklearn/tree/_criterion.pxd

@@ -65,11 +65,6 @@ cdef class Criterion:
     cdef double impurity_improvement(self, double impurity) nogil
     cdef double proxy_impurity_improvement(self) nogil
 
-    cdef double node_impurity2(self, double* pred_weights) nogil
-    cdef void children_impurity2(self, double* impurity_left,
-                                double* impurity_right, double* pred_weights) nogil
-    cdef double proxy_impurity_improvement2(self, double* pred_weights) nogil
-
 cdef class ClassificationCriterion(Criterion):
     """Abstract criterion for classification."""
 
@@ -80,8 +75,4 @@ cdef class RegressionCriterion(Criterion):
     """Abstract regression criterion."""
 
     cdef double sq_sum_total
-
-cdef class ObliqueProjection(RegressionCriterion):
-    pass
-cdef class AxisProjection(RegressionCriterion):
-    pass
+    cdef object random_state         # Random state for predictor weights (Projection-Based Splitters)