July 5th, 2017, 03:48 AM  #1 
Newbie Joined: Jun 2017 From: italia Posts: 13 Thanks: 2  How many rounds?
A particle is moving along a circle CCW with almost constant speed. I sample the x and y coordinates of the particle to get a point every degree or so (usually 1 point every 0.5 to 1.5 degrees). Since I need to stop the sampling after a given number of rounds, I need to count how many rounds the particle has done so far. 
July 5th, 2017, 04:41 AM  #2 
Global Moderator Joined: Dec 2006 Posts: 19,865 Thanks: 1833 
Do you mean you want to count the number of completed rounds?

July 5th, 2017, 06:24 AM  #3 
Newbie Joined: Jun 2017 From: italia Posts: 13 Thanks: 2 
Yep! (Sorry for my English.)

July 5th, 2017, 11:25 AM  #4 
Senior Member Joined: Aug 2012 Posts: 2,075 Thanks: 593 
If the motion is always in the same direction, you can tell that it's gone around once when it appears to go backwards. In other words if the angle (between the ray from the origin to your point, and the positive xaxis) decreases. In other words if the angle is 45 degrees on one measurement and 44 degrees on the next, it must have gone around 359 degrees. 

Tags 
rounds 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Linear algebra to represent 2 rounds elections  Appiani  Linear Algebra  0  December 10th, 2015 03:40 AM 
9 Rounds  yudencow  Number Theory  2  December 19th, 2012 09:43 PM 