# Thread: Lonely and not so lonely caches

1. My first post. This thread made me to register. There is some serious science going on here

Looks like your macro is running in O(n^2) or worse time complexity. You however, don't need to check every couple of caches. There is an algorithm that runs in O(n log n) time complexity. You just need to find Delaunay triangulation because is is dual problem to Voronoi and check only edges for maximum distance.

http://en.wikipedia.org/wiki/Delaunay_triangulation
http://en.wikipedia.org/wiki/Voronoi_diagram

or you can just take results from my webpage
http://mgs.cano.sk/proximity.php

2. HUH??? What was that all about? I doubt even Brdad could even figure that one out.... And besides we use miles here and not kilometers...lol

3. Senior Member
Join Date
May 2009
Location
Orlando, Florida
Posts
285
Originally Posted by cano
You just need to find Delaunay triangulation because is is dual problem to Voronoi and check only edges for maximum distance.
Haha, "just". Don't click on his wikipedia links... they made me so confused that I spent the morning alternating between crying and banging my head on my desk.

4. Originally Posted by Haffy
And besides we use miles here and not kilometers...lol
Haffy - Cano is from Bangor. Although he's a newcomer on GCM.org, he's been to several of the local events. (Sheesh! Just because he appears smarter than you - and possibly me... )

5. I thought it was funny haffy used the word "here" and he's not "here"! But I know you're here in spirit, John, and miss you at all the events.

Welcome to the registered side of gcmaine, cano.

I think haffy may be right in one thing, I'm not sure I understand those links! And perhaps I should stick to WHEN the next nth cache will be placed instead of WHERE! But I will look again when my mind isn't busy elsewhere.
Last edited by brdad; 09-23-2009 at 04:29 PM.

I thought it was funny haffy used the word "here" and he's not "here"! But I know you're here in spirit, John, and miss you at all the events.
"Here" as in the good ole USA not necessarily where "I" am right now and not in Slovakia or where ever Cano is originally from....

7. km vs miles, I just knew radius of Earth in km and was lazy to convert it to miles, so I used km in my calculations.

I thought you are looking for the loneliest cache
You cannot predict place, because placing caches is a random process, however you can find an area with the highest probability for given radius easily and precisely using evolution algorithms. If you are OK with just approximate solution you can find and area around an existing cache which has the most caches in it for given radius easily in O(n^2) time

About predicting a precise time of next milestones... I can look at it

8. It's not your fault Cano, I think the USA is about the only country in the world that hasn't converted to the metric system yet.

9. Originally Posted by Haffy
It's not your fault Cano, I think the USA is about the only country in the world that hasn't converted to the metric system yet.
There are actually 3 countries in the world that don't use metric system yet. USA and some two small African countries. But they don't have anything to measure anyway so it doesn't matter for them which system they use for measures.

Anyway, for this purpose it doesn't matter what units are used. I could tell you it is miles or feet without changing the numbers and nobody would noticed

10. Originally Posted by Haffy
It's not your fault Cano, I think the USA is about the only country in the world that hasn't converted to the metric system yet.
I wish people had voted for the metric system back in... when was it, around 1975 maybe? By now, it would have been a good change. I was too young and most of the older fuddy-duddies were against learning anything new.
Last edited by brdad; 09-23-2009 at 05:09 PM.

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