Comments on: PHP Content Rating / Confidence http://www.derivante.com/2009/09/01/php-content-rating-confidence/ to obtain or receive from a source Sat, 30 Jul 2011 08:51:15 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Alix Axel http://www.derivante.com/2009/09/01/php-content-rating-confidence/comment-page-1/#comment-573 Alix Axel Fri, 15 Apr 2011 12:20:10 +0000 http://www.derivante.com/?p=717#comment-573 Just a quick note: if you have the stats extension installed you can replace the pnormaldist() function with a call to the built-in function stats_cdf_normal($power, 0, 1, 2). In my tests it has proven to be slightly more accurate than the pnormaldist() implementation. Just a quick note: if you have the stats extension installed you can replace the pnormaldist() function with a call to the built-in function stats_cdf_normal($power, 0, 1, 2).

In my tests it has proven to be slightly more accurate than the pnormaldist() implementation.

]]> By: i-g http://www.derivante.com/2009/09/01/php-content-rating-confidence/comment-page-1/#comment-372 i-g Sat, 24 Oct 2009 06:01:23 +0000 http://www.derivante.com/?p=717#comment-372 What is the significance of the numbers that you populate into the $b array? I don't understand where they come from. What is the significance of the numbers that you populate into the $b array? I don’t understand where they come from.

]]> By: Daniel Errante http://www.derivante.com/2009/09/01/php-content-rating-confidence/comment-page-1/#comment-350 Daniel Errante Sat, 03 Oct 2009 22:15:27 +0000 http://www.derivante.com/?p=717#comment-350 Ok, that answers my question. Thanks for all the information! I have another question though: What if I just want to add the gravity part to the MySQL query? For example, if I already have my score variable as $score, and i have the date as add_date, how do I weight newer content to show up higher in the results and then slowly fall back into place over time? Ok, that answers my question. Thanks for all the information! I have another question though:

What if I just want to add the gravity part to the MySQL query? For example, if I already have my score variable as $score, and i have the date as add_date, how do I weight newer content to show up higher in the results and then slowly fall back into place over time?

]]> By: Clay vanSchalkwijk http://www.derivante.com/2009/09/01/php-content-rating-confidence/comment-page-1/#comment-295 Clay vanSchalkwijk Fri, 18 Sep 2009 13:53:36 +0000 http://www.derivante.com/?p=717#comment-295 You could port the formula to a stored procedure but if you're concerned about the time it takes to process the result set into a cache, doing it on the fly on every record each time will be far worse. My recommendation would be to just have a hook into your voting to recalculate just the row being voted on and process any record within your decay time through cron. After the decay time, the score should not change until a vote is issued so there is no point to re-calculate this on the fly and the newer records will represent a smaller subset of your overall data which should reduce the number of records you need to process. If you do want to port over the code above, all the math functions are available within SQL: http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html http://dev.mysql.com/doc/refman/5.0/en/create-procedure.html You could port the formula to a stored procedure but if you’re concerned about the time it takes to process the result set into a cache, doing it on the fly on every record each time will be far worse.

My recommendation would be to just have a hook into your voting to recalculate just the row being voted on and process any record within your decay time through cron.

After the decay time, the score should not change until a vote is issued so there is no point to re-calculate this on the fly and the newer records will represent a smaller subset of your overall data which should reduce the number of records you need to process.

If you do want to port over the code above, all the math functions are available within SQL:

http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html

http://dev.mysql.com/doc/refman/5.0/en/create-procedure.html

]]> By: danoph http://www.derivante.com/2009/09/01/php-content-rating-confidence/comment-page-1/#comment-291 danoph Fri, 18 Sep 2009 03:27:34 +0000 http://www.derivante.com/?p=717#comment-291 Is there a way that the formula could be written to support real time calculating? I need a one-liner solution that favors more popular items but also throws newer results in the top of the mix and decays those results over time, like you mentioned above. I could solve this problem by caching these values, but I would have to update a database of tens of thousands of records multiple times a day, correct? I am using the expression sorting method as mentioned here in my search engine: http://www.sphinxsearch.com/docs/current.html#sorting-modes Is there a way that the formula could be written to support real time calculating? I need a one-liner solution that favors more popular items but also throws newer results in the top of the mix and decays those results over time, like you mentioned above. I could solve this problem by caching these values, but I would have to update a database of tens of thousands of records multiple times a day, correct? I am using the expression sorting method as mentioned here in my search engine: http://www.sphinxsearch.com/docs/current.html#sorting-modes

]]> By: Clay vanSchalkwijk http://www.derivante.com/2009/09/01/php-content-rating-confidence/comment-page-1/#comment-264 Clay vanSchalkwijk Sun, 13 Sep 2009 00:37:03 +0000 http://www.derivante.com/?p=717#comment-264 You do not want to do this calculation on the fly with MySQL. It makes more sense to cache the score and let MySQL handle the sorting. Otherwise you are calculating scoring for each row on each page load. This will seriously hurt your application performance. You do not want to do this calculation on the fly with MySQL. It makes more sense to cache the score and let MySQL handle the sorting.

Otherwise you are calculating scoring for each row on each page load. This will seriously hurt your application performance.

]]> By: Daniel Errante http://www.derivante.com/2009/09/01/php-content-rating-confidence/comment-page-1/#comment-255 Daniel Errante Wed, 09 Sep 2009 07:10:06 +0000 http://www.derivante.com/?p=717#comment-255 How would I go about implementing a MySQL version of the wilson score interval? How would I go about implementing a MySQL version of the wilson score interval?

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