Update xorshift.py

bug fix and added some methods
(value, rangefloat)

src/xorshift.py

@@ -37,13 +37,46 @@ class Xorshift(object):
 
         return self.w
 
-    def range(mi,ma):
+    def advances(self,length:int):
+        self.getNextRandSequence(self)
+
+    def range(self,mi:int,ma:int)->int:
+        """generate random integer value in [mi,ma)
+
+        Args:
+            mi ([int]): minimum
+            ma ([int]): maximam
+
+        Returns:
+            [int]: random integer value
+        """
         return self.next() % (ma-mi) + min
 
-    def getNextRandSequence(length):
+    def value(self)->float:
+        """generate random value in [0,1]
+
+        Returns:
+            float: random value
+        """
+        return (self.next() & 0x7fffff) / 8388607.0
+
+    def rangefloat(self,mi:float,ma:float)->float:
+        """generate random value in [mi,ma]
+
+        Args:
+            mi (float): minimum
+            ma (float): maximam
+
+        Returns:
+            [type]: [description]
+        """
+        t = self.value()
+        return t * mi + (1-t) * ma
+
+    def getNextRandSequence(self,length):
         return [self.next() for _ in range(length)]
 
-    def getPrevRandSequence(length):
+    def getPrevRandSequence(self,length):
         return [self.prev() for _ in range(length)]
 
     def getState(self):