Changes:迭代方差计算

variance_x.py

@@ -0,0 +1,32 @@
+from algorithm import algorithm
+import json
+import ray
+
+@ray.remote
+class variance_x(algorithm):
+    def __init__(self):
+        self.config_dict_ = None
+        self.config_ = None
+        self.window_length_ = 10
+        self.avg_ = 0
+        self.var_ = 0
+
+    def set_config(self, config):
+        self.config_ = config
+        self.config_dict_ = json.loads(self.config_)
+        self.window_length_ = self.config_dict_["WINDOW_LENGTH"]
+        self.init_flag_ = False
+
+    def config(self):
+        return self.config_
+
+    def eval(self, value):
+        if self.init_flag_ == False:
+            self.init_flag_ = True
+            self.avg_ = value
+            self.var_ = 0
+        else:
+            present_avg_ = self.avg_ * (self.window_length_ - 1)/self.window_length_ + value / self.window_length_
+            self.var_ = self.var_ +(value - present_avg_) * (value-self.avg_)
+            self.avg_ = present_avg_
+        return self.var_