Merge pull request algorithm-archivists#2 from KingFredrickVI/master

Added Python example for Verlet

Author: leios

chapters/computational_physics/verlet.md

@@ -252,3 +252,83 @@ public static void main(String[] args) {
  
 }
 ```
+
+#### Python
+
+```Python
+
+# KingFredrickVI
+
+
+class Ball:
+
+    def __init__(self, pos=0, vel=0, acc=0):
+        self.pos = pos
+        self.vel = vel
+        self.acc = acc
+
+
+class Simulation:
+
+    def __init__(self, obj, dt = 0.01):
+        self.obj = obj
+        self.dt = dt
+        self.prev_pos = self.obj.pos
+
+    def run(self):
+        self.time = 0
+
+        while self.obj.pos > 0:
+            self.time += self.dt
+            self.step()
+
+    def step(self):
+        pass
+
+
+class Verlet(Simulation):
+    
+    def step(self):
+        temp_pos = self.obj.pos
+        self.obj.pos = self.obj.pos * 2 - self.prev_pos + self.obj.acc * self.dt * self.dt
+        self.prev_pos = temp_pos
+
+
+class Stormer_Verlet(Simulation):
+
+    def step(self):
+        temp_pos = self.obj.pos
+        self.obj.pos = self.obj.pos * 2 - self.prev_pos + self.obj.acc * self.dt * self.dt
+        self.prev_pos = temp_pos
+
+        self.obj.vel += self.obj.acc * self.dt
+
+
+class Velocity_Verlet(Simulation):
+
+    def step(self):
+        self.obj.pos += self.obj.vel * self.dt + 0.5 * self.obj.acc * self.dt * self.dt
+        self.obj.vel += self.obj.acc * self.dt
+
+
+def main():
+    sim = Verlet(Ball(pos = 5.0, acc = -10))
+    sim.run()
+
+    print "Verlet:", sim.time
+
+    sim = Stormer_Verlet(Ball(pos = 5.0, acc = -10))
+    sim.run()
+
+    print "Stormer Verlet:", sim.time
+
+    sim = Velocity_Verlet(Ball(pos = 5.0, acc = -10))
+    sim.run()
+
+    print "Velocity Verlet:", sim.time
+
+
+if __name__ == "__main__":
+    main()
+
+```