add hist mock

Signed-off-by: weiwee <wbwmat@gmail.com>

python/fate/arch/tensor/inside/__init__.py

@@ -1 +1,2 @@
+from ._op_hist import Hist
 from ._op_quantile import GKSummary

python/fate/arch/tensor/inside/_op_hist.py

@@ -0,0 +1,45 @@
+class Hist:
+    def __init__(self):
+        self.data = {}
+
+    def update(self, features, labels):
+        shape_x, shape_y = features.shape
+        for i in range(shape_x):
+            for j in range(shape_y):
+                v = features[i, j]
+                if j not in self.data:
+                    self.data[j] = {}
+                if v not in self.data[j]:
+                    self.data[j][v] = labels[i]
+                else:
+                    self.data[j][v] += labels[i]
+
+    def merge(self, hist):
+        for k in hist.data:
+            if k not in self.data:
+                self.data[k] = hist.data[k]
+            else:
+                for kk in hist.data[k]:
+                    if kk not in self.data[k]:
+                        self.data[k][kk] = hist.data[k][kk]
+                    else:
+                        self.data[k][kk] += hist.data[k][kk]
+        return self
+
+    def cumsum(self):
+        for k in self.data:
+            s = 0
+            for kk in sorted(self.data[k].keys()):
+                s += self.data[k][kk]
+                self.data[k][kk] = s
+        return self
+
+
+if __name__ == "__main__":
+    import numpy as np
+
+    hist = Hist()
+    features = np.array([[1, 0], [0, 1], [2, 1], [2, 0]])
+    labels = np.array([0, 1, 0, 0])
+    hist.update(features, labels)
+    print(hist.data)