LFD Book Forum  

Go Back   LFD Book Forum > Course Discussions > Online LFD course > Homework 3

Reply
 
Thread Tools Display Modes
  #11  
Old 04-21-2013, 08:11 AM
IsidroHidalgo IsidroHidalgo is offline
Member
 
Join Date: Apr 2013
Location: Toledo (Spain)
Posts: 28
Default Re: Concentric circles in Q10

But I finally don't have a clear idea of the center of our hypothesis here: is always x_1=0 and x_2=0 or not?
Reply With Quote
  #12  
Old 04-21-2013, 08:56 AM
Elroch Elroch is offline
Invited Guest
 
Join Date: Mar 2013
Posts: 143
Default Re: Concentric circles in Q10

Quote:
Originally Posted by IsidroHidalgo View Post
But I finally don't have a clear idea of the center of our hypothesis here: is always x_1=0 and x_2=0 or not?
Well, x_1 and x_1 are the variables, but the centre is at (0,0) as indicated in yaser's post #2.
Reply With Quote
  #13  
Old 04-21-2013, 09:56 AM
marek marek is offline
Member
 
Join Date: Apr 2013
Posts: 31
Default Re: Concentric circles in Q10

You can choose your points however you want. So fix any layout of points by drawing them on a piece of piece of paper. If you translate all the points by moving that piece of paper around, the new positions are another set of points which you could have chosen.

So in a sense you can consider any layout of points and then start the circles where ever you wanted. The trick is that once you pick a spot for the centers of the circles you have to keep that same center for all the dichotomies you're generating.

And that does also mean that you can assume one point is in the center if you want.
Reply With Quote
  #14  
Old 04-21-2013, 10:26 AM
IsidroHidalgo IsidroHidalgo is offline
Member
 
Join Date: Apr 2013
Location: Toledo (Spain)
Posts: 28
Default Re: Concentric circles in Q10

But he says to in #5 "so the origin is effectively arbitrary", so there's a little confusion here for me...
Reply With Quote
  #15  
Old 04-21-2013, 11:06 AM
marek marek is offline
Member
 
Join Date: Apr 2013
Posts: 31
Default Re: Concentric circles in Q10

Quote:
Originally Posted by IsidroHidalgo View Post
But he says to in #5 "so the origin is effectively arbitrary", so there's a little confusion here for me...
That's what I'm trying to address in my above post.

Let me make my analogy a little more substantial. Let's say your grid and origin are fixed on your desk. The paper you draw your points on is transparent. You can slide around that transparency as you want, since your choice of points is up to you. But from the perspective of the points on the transparency, the points are fixed but the origin is sliding around. That is what he's referring to by saying the origin is effectively arbitrary.

Once you pick your points, you can put your origin anywhere you want (though the actual mechanic is that you're making new set of points that are appropriately translated with respect to the origin and using them instead)
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 07:14 AM.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
The contents of this forum are to be used ONLY by readers of the Learning From Data book by Yaser S. Abu-Mostafa, Malik Magdon-Ismail, and Hsuan-Tien Lin, and participants in the Learning From Data MOOC by Yaser S. Abu-Mostafa. No part of these contents is to be communicated or made accessible to ANY other person or entity.