Re: [PHP] Seeking overlap algorithm
On Dec 6, 2007 9:14 PM, tedd [EMAIL PROTECTED] wrote: At 6:07 PM -0500 12/6/07, Nathan Nobbe wrote: On Dec 6, 2007 4:59 PM, tedd [EMAIL PROTECTED] wrote: The problem is, could you guarantee to a preferred service provider that they would receive top-listing 25 percent of the time? Keep in mind that preferred service providers will overlap. So, the question is how to accommodate for that overlap? If anyone has an algorithm, I would be interested in hearing it. i think that should be pretty easy. the algorithm is dependent upon 2 values. the number of listings you consider as top-listings for each result set and the number of customers that are registered as preferred customers. let me illustrate. imagine you designate only the first entry of the resultant listings as a * top-listing*. in that case you can support a maximum of 4 preferred customers before you can no longer guarantee to each of the preferred customers their listing will be a top-listing 25% of the time. so, if you want more capacity you can increase the number of results that are designated as top-listing results. suppose you increase the number to 2, now you have a capacity of 8 customers you can guarantee top-listing status 25% of the time. what you would need to determine is what to do if ever you didnt want to increment the number of listings that are designated as top-listing customers and you were already at capacity for the number of customers the current capacity supports. Yes, that was pretty easy, but that was not the answer to the question -- my error for not explaining it better. Let me rephrase the question by providing an example. Let's say we have a customer base that is spread-out at random over a geographic area. Each customer has designated a 50 mile radius from their location as being within their zone -- the map would look like a bomb saturation map, if you know what I mean. Now, many of those areas overlap so that if a end-user is within that overlap he can see all the service providers that can provide service. It's a simple matter to pull those providers out of a database depending upon distance and show them to him. After all, that's the way it works, isn't it? The end-user is provided all the service providers who are within their service range. However, if you are also considering that some of these service providers should be shown as preferred (i.e., at the top 25 percent of the time) then you might find yourself in a position of over selling the top position because there may be too many preferred service providers in certain areas. Now, what I need is a way to analyze the distribution of the current service providers to see if a given location is open to being sold as a preferred position -- do you see what I mean? Another example, let's say we have four preferred service providers at the same location. Obviously, we could not sell another preferred position within 100 miles. Another example, let's say we have four preferred service providers 100 miles apart, clearly we can sell more preferred positions. But, the number of positions available depends upon the distribution of the original four. If they were located in a straight line, then we could sell two positions between each one. But, if they were distributed in a square, we could only sell one. Do you see? I know what solution I will be using unless someone comes up with something different. I just want to tap this knowledgeable group before I spin my wheels trying to solve a problem, that may be already solved. i see the problem more clearly now. unfortunately, i dont know the solution off the top of my head :( if i think of something in the near future ill toss it on the list. -nathan
RE: [PHP] Seeking overlap algorithm
On 07 December 2007 02:14, tedd wrote: Now, what I need is a way to analyze the distribution of the current service providers to see if a given location is open to being sold as a preferred position -- do you see what I mean? Another example, let's say we have four preferred service providers at the same location. Obviously, we could not sell another preferred position within 100 miles. Another example, let's say we have four preferred service providers 100 miles apart, clearly we can sell more preferred positions. But, the number of positions available depends upon the distribution of the original four. If they were located in a straight line, then we could sell two positions between each one. But, if they were distributed in a square, we could only sell one. Do you see? A simplistic but effective way would be: (1) Locate all preferred providers within 50 miles of the potential new one (presumably a maximum of four!). (2) For each of these, find how many suppliers are within their 50-mile catchment radius. If any of the answers at step 2 is four, you lose; if none of them is, you win. I can't think of any obvious ways to optimize this, but then I never did properly get the travelling salesman or 4-colour problem! Cheers! Mike - Mike Ford, Electronic Information Services Adviser, JG125, The Headingley Library, James Graham Building, Leeds Metropolitan University, Headingley Campus, LEEDS, LS6 3QS, United Kingdom Email: [EMAIL PROTECTED] Tel: +44 113 812 4730 Fax: +44 113 812 3211 To view the terms under which this email is distributed, please go to http://disclaimer.leedsmet.ac.uk/email.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Seeking overlap algorithm
On Dec 7, 2007 10:12 AM, Ford, Mike [EMAIL PROTECTED] wrote: On 07 December 2007 02:14, tedd wrote: Now, what I need is a way to analyze the distribution of the current service providers to see if a given location is open to being sold as a preferred position -- do you see what I mean? Another example, let's say we have four preferred service providers at the same location. Obviously, we could not sell another preferred position within 100 miles. Another example, let's say we have four preferred service providers 100 miles apart, clearly we can sell more preferred positions. But, the number of positions available depends upon the distribution of the original four. If they were located in a straight line, then we could sell two positions between each one. But, if they were distributed in a square, we could only sell one. Do you see? A simplistic but effective way would be: (1) Locate all preferred providers within 50 miles of the potential new one (presumably a maximum of four!). (2) For each of these, find how many suppliers are within their 50-mile catchment radius. If any of the answers at step 2 is four, you lose; if none of them is, you win. I can't think of any obvious ways to optimize this, but then I never did properly get the travelling salesman or 4-colour problem! im ashamed to admit i blew off a couple of linear algebra classes and a calc-based stats class in college. had i paid attention, this might still be a trivial problem =/ ..., bah! -nathan
[PHP] Seeking overlap algorithm
Hi gang: This post is related to the zip lat/long request I recently made and received such an overwhelming response -- many thanks to all. In any event, let's say we have a end-user who is looking for services within his zip-code AND we have a dB of service providers who are willing to render service within a set distance (like 50 miles) from their location. Now, it's a simple matter to convert the user's zip code to lat/longs and then find out how many service providers there are within their area and then show that list to the end-user. That's not the problem. The problem is, could you guarantee to a preferred service provider that they would receive top-listing 25 percent of the time? Keep in mind that preferred service providers will overlap. So, the question is how to accommodate for that overlap? If anyone has an algorithm, I would be interested in hearing it. Cheers, tedd -- --- http://sperling.com http://ancientstones.com http://earthstones.com -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Seeking overlap algorithm
On Dec 6, 2007 4:59 PM, tedd [EMAIL PROTECTED] wrote: Hi gang: This post is related to the zip lat/long request I recently made and received such an overwhelming response -- many thanks to all. In any event, let's say we have a end-user who is looking for services within his zip-code AND we have a dB of service providers who are willing to render service within a set distance (like 50 miles) from their location. Now, it's a simple matter to convert the user's zip code to lat/longs and then find out how many service providers there are within their area and then show that list to the end-user. That's not the problem. The problem is, could you guarantee to a preferred service provider that they would receive top-listing 25 percent of the time? Keep in mind that preferred service providers will overlap. So, the question is how to accommodate for that overlap? If anyone has an algorithm, I would be interested in hearing it. i think that should be pretty easy. the algorithm is dependent upon 2 values. the number of listings you consider as top-listings for each result set and the number of customers that are registered as preferred customers. let me illustrate. imagine you designate only the first entry of the resultant listings as a * top-listing*. in that case you can support a maximum of 4 preferred customers before you can no longer guarantee to each of the preferred customers their listing will be a top-listing 25% of the time. so, if you want more capacity you can increase the number of results that are designated as top-listing results. suppose you increase the number to 2, now you have a capacity of 8 customers you can guarantee top-listing status 25% of the time. what you would need to determine is what to do if ever you didnt want to increment the number of listings that are designated as top-listing customers and you were already at capacity for the number of customers the current capacity supports. perhaps you could start charging more at that point. -nathan
Re: [PHP] Seeking overlap algorithm
At 6:07 PM -0500 12/6/07, Nathan Nobbe wrote: On Dec 6, 2007 4:59 PM, tedd [EMAIL PROTECTED] wrote: The problem is, could you guarantee to a preferred service provider that they would receive top-listing 25 percent of the time? Keep in mind that preferred service providers will overlap. So, the question is how to accommodate for that overlap? If anyone has an algorithm, I would be interested in hearing it. i think that should be pretty easy. the algorithm is dependent upon 2 values. the number of listings you consider as top-listings for each result set and the number of customers that are registered as preferred customers. let me illustrate. imagine you designate only the first entry of the resultant listings as a * top-listing*. in that case you can support a maximum of 4 preferred customers before you can no longer guarantee to each of the preferred customers their listing will be a top-listing 25% of the time. so, if you want more capacity you can increase the number of results that are designated as top-listing results. suppose you increase the number to 2, now you have a capacity of 8 customers you can guarantee top-listing status 25% of the time. what you would need to determine is what to do if ever you didnt want to increment the number of listings that are designated as top-listing customers and you were already at capacity for the number of customers the current capacity supports. Yes, that was pretty easy, but that was not the answer to the question -- my error for not explaining it better. Let me rephrase the question by providing an example. Let's say we have a customer base that is spread-out at random over a geographic area. Each customer has designated a 50 mile radius from their location as being within their zone -- the map would look like a bomb saturation map, if you know what I mean. Now, many of those areas overlap so that if a end-user is within that overlap he can see all the service providers that can provide service. It's a simple matter to pull those providers out of a database depending upon distance and show them to him. After all, that's the way it works, isn't it? The end-user is provided all the service providers who are within their service range. However, if you are also considering that some of these service providers should be shown as preferred (i.e., at the top 25 percent of the time) then you might find yourself in a position of over selling the top position because there may be too many preferred service providers in certain areas. Now, what I need is a way to analyze the distribution of the current service providers to see if a given location is open to being sold as a preferred position -- do you see what I mean? Another example, let's say we have four preferred service providers at the same location. Obviously, we could not sell another preferred position within 100 miles. Another example, let's say we have four preferred service providers 100 miles apart, clearly we can sell more preferred positions. But, the number of positions available depends upon the distribution of the original four. If they were located in a straight line, then we could sell two positions between each one. But, if they were distributed in a square, we could only sell one. Do you see? I know what solution I will be using unless someone comes up with something different. I just want to tap this knowledgeable group before I spin my wheels trying to solve a problem, that may be already solved. Thanks, for your time. Cheers, tedd -- --- http://sperling.com http://ancientstones.com http://earthstones.com -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
