/Recommender_Bayes.class.php

<?php
/*********************************************************** 
 * Recommender Class -- Bayes/memcache version
 *
 *	06/16/2009 -- KEL created Bayes/Memcache fork for 2009 version
 * Created 08/07/2007 by Kristian Ljungkvist Based on Recommender test bed work.
 *
 * Copyright 2007 Science Buddies. All Rights Reserved
 ************************************************************/ 
require_once 'sciencebuddies/Error.class.php';
require_once 'sciencebuddies/Database.class.php';
require_once 'sciencebuddies/Modifier.class.php';

class Recommender
{

	var $sk_summary = array();
	var $configuration = array();
	var $memcache_handle = null;
	var $DB_Connection = null;
	var $dataset_filename = "";


	/**
		* Constructor
		*
		*
		* @author Kristian Ljungkvist
		*/
	function	__construct($db,$originID,$dataset,$memcache)	{
		// Bayes/memcache version uses dataset as a prefix into memcache for the various datasets.
		if(!$db) {
			// No database handle is considered a critical error.
			trigger_error("No Database handle passed to Recommender constructor",E_USER_ERROR);
			exit;
		}
		if(!$memcache) {
				// No memcache handle is considered a critical error.
				trigger_error("No Memcache handle passed to Recommender constructor",E_USER_ERROR);
				exit;
			
		}
		// Now, get configuration for recommender with the current originID -- default: 1.		
		$this->DB_Connection = $db;
		$sql = "SELECT * FROM recommender_config where originID=$originID";

		$this->configuration = $this->DB_Connection->query($sql);

		$this->memcache_handle = $memcache;
		$this->dataset_filename = $dataset;
		$this->sk_summary = $memcache->get("$dataset:sk_summary");
	}

	/**
		* individual_ranking
		*
		* Returns the ranking of SKs for the current dataset and the individual passed in.
		* @author Kristian Ljungkvist
		*/

	function individual_ranking($ind_summary) {


		$ranking_array = $this->algorithm_bayes($ind_summary,4,$mof,0,0, $this->dataset_filename, $this->memcache_handle);
	//	$ranking_array = $this->algorithm070220h($this->sk_summary,$ind_summary,4);

		// KEL 10/18/07 -- Also tag the resulting ranking with the ProfileID of the profile that created it.
		// We'll use leading underscores on the header information here to make it easy for other phases to strip these out of displayed result sets.

		$ranking_array['_Source'] = 'Individual';
		$ranking_array['_SourceProfile'] = $ind_summary['ProfileID'];
		// KEL 09/18/2008 -- Also tag the ranking with the time stamp of the dataset that was used.
		// This is so that we can check for updated datasets and invalidate the cache in those cases.
		$stat_array = stat("./project_ideas/development/".$this->dataset_filename);
		$ranking_array['_DatasetModTime'] = $stat_array['mtime'];
		
		$ranking_array['_DatasetFilename'] = $this->dataset_filename; 	// KEL 06/24/09 -- Store the originating dataset filename for future reference
																		// since we'll have several "neighborhood" datasets.

		return $ranking_array;
	}


	/**
		* show_others_like_this
		*
		* Returns the ranking of SKs against the passed-in SK.
		* @author Kristian Ljungkvist
		*/

	function show_others_like_this($solt_sk) {
		// get profile for the source project 
		// Look up title for this SK.
		preg_match('/^([^_]+)/', $solt_sk, $match);
		$subarea = $match[0];

		$source_project_profile = $this->sk_summary[$subarea]['SKs'][$solt_sk];

		// Generate the ranking of that project against the others
		
		// NOTE: We need to generate the project profile somehow in the new Bayes context. We'll most likely need to store one record per project in memcache with
		// the project profile. This will need to happen in the add_to_memcache utility.
		$ranking_array = $this->algorithm_bayes($source_project_profile,4,$mof,0,0, $this->dataset_filename, $this->memcache_handle);


		// KEL 10/18/07 -- Also tag the resulting ranking with the source and the ProfileID of the profile that created it.
		// We'll use leading underscores on the header information here to make it easy for other phases to strip these out of displayed result sets.

		$ranking_array['_Source'] = 'Project';
		$ranking_array['_SourceProfile'] = $solt_sk; // For show others like this, we'll use the project filename as the source ID.
		
		// KEL 09/18/2008 -- Also tag the ranking with the time stamp of the dataset that was used.
		// This is so that we can check for updated datasets and invalidate the cache in those cases.
		$stat_array = stat("./project_ideas/development/".$this->dataset_filename);
		$ranking_array['_DatasetModTime'] = $stat_array['mtime'];

		return $ranking_array;
	}


	/**
		* static_ranking
		*
		* Essentially converts the current dataset into a "ranking" of the form the rendering methods expect.
		* Used for the dynamic interest area pages.
		* @author Kristian Ljungkvist 05/21/08
		*/

	function static_ranking() {
		
		// Convert the sk_summary member to the SK->MSD form. We'll set all MSD's to 1.0 for this "ranking"
		
		foreach($this->sk_summary as $subarea => $subarea_array) {
			foreach($subarea_array['SKs'] as $SK => $SK_array) {
				$ranking_array[$SK] = 1.0;
			}
		}

		$ranking_array['_Source'] = 'Individual';
		$ranking_array['_SourceProfile'] = $ind_summary['ProfileID'];

		// KEL 09/18/2008 -- Also tag the ranking with the time stamp of the dataset that was used.
		// This is so that we can check for updated datasets and invalidate the cache in those cases.
		$stat_array = stat("./project_ideas/development/".$this->dataset_filename);
		$ranking_array['_DatasetModTime'] = $stat_array['mtime'];

		return $ranking_array;
	}



	function algorithm_bayes($individual_array,$threshold,$mof,$recenter,$gcv, $dataset, $memcache) {
		// Get list of prior probabilities
		$prior_probabilities_list = $memcache->get("$dataset:prior_prob");
		
		echo "algorithm_bayes:prior_probabilities_list:<br/>";
		echo "<pre/>".print_r($prior_probabilities_list)."</pre>";

		$MATURITY = 3; // offset in to the answer_list for the maturity


		$unordered_ranking = array();
		$project_prob = 1;

		$num_matching_questions = 0; // keeps track of the total number of matching questions between ind and project.
		$highest_maturity = 0; // records the maturity of the most mature question
		$skipped_questions = 0;
		$matching_questions_ref = array();
		$highest_maturities_ref = array();
		$question_maturity_threshold = 100;

		foreach($individual_array['Questions'] as $question => $user_answer) {
			// 		Grab the corresponding project data list from memcached.
			$project_list = $memcache->get("$dataset:$question:$user_answer");
			$project_maturity_list = $memcache->get("$dataset:$question:3");
			foreach($project_list as $project => $answer_prob) {
				$proj_ptr = &$unordered_ranking[$project]; // get a pointer to the project in the ranking. Speeds things up quite a bit.
				$maturity_ptr = &$project_maturity_list[$project];
				if($answer_prob == 0) {continue;}
				if($maturity_ptr > $question_maturity_threshold) {
					if(!$proj_ptr) {
						$proj_ptr = 1.0;
					}
					$proj_ptr = $proj_ptr * $answer_prob;

					$mqr_ptr = &$matching_questions_ref[$project];
					$mqr_ptr++;  
					$project_hmr_ptr = &$highest_maturity_ref[$project];
					if($maturity_ptr > $project_hmr_ptr) {
						$project_hmr_ptr = $maturity_ptr;
					}
				}
			}
		}

		// Now need to loop through the projects and do the nth root/ prior probability calculations.
		$include_prior_probability = 1;
		foreach($matching_questions_ref as $project => $num_matching_questions) {					
			$unordered_ranking[$project] = $unordered_ranking[$project] * $prior_probabilities_list[$project]; // Multiply by the prior probability.
			$unordered_ranking[$project] = pow($unordered_ranking[$project],(1 / ($num_matching_questions +1))); // Take the nth root where n = number of matching questions for this project.
			if(($unordered_ranking[$project] < 1) && ($highest_maturity_ref[$project] > $threshold)) {
				$filtered_unordered_ranking[$project] = $unordered_ranking[$project];
			}
		}
		// Now sort the unordered ranking
		arsort($filtered_unordered_ranking);

		$ranking_array = $filtered_unordered_ranking;
		foreach($ranking_array as $SK => $prob) {
			$return_ranking[$SK] = $prob;
		}
		return($return_ranking);
	}



	/**
		* function algorithm070220h
		*
		**/
	function algorithm070220h($big_array,$individual_array,$threshold,$mof,$recenter,$gcv) {

		// big_array holds an entire subject area. Individual_array is one individual's responses.
		$squared_diff = array();
		$absolute_diff = array();
		$MSD = array();
		$MAV = array();
		$SAV = array();

		// "<hr/>gcv = $gcv, recenter = $recenter<hr/>";
		if(!$recenter) {
			if($this->configuration['GlobalRecenterValue'] > 0) {
				$recenter = true;
				$gcv = $this->configuration['GlobalRecenterValue'];
			}
		}
		if($recenter) {
			/** If recenter == True, alter the individual_array by recentering the values:
			*
				* 1) Calculate the overall average of all the questions that the user answered = UserAvg 
				* 2)  Calculate a re-centering value for the user: 
			*  UserOffset = UserAvg ? GlobalCenterValue  [from the template] 
				* 3)  Before calculating either the squared or absolute difference, adjust the user values in the $individual_array, for each question: 
			* NewUserValuei = OldUserValuei ? UserOffset 
				**/

			if(!isset($gcv)) {
				$gcv = 1; // Default Global Center Value to 1
			}
			$usercount = 0;
			$usertotal = 0;
			foreach($individual_array['Questions'] as $question => $answer) {
				if(!preg_match("/^_/", $question)) { 
					continue;// Skip questions other than "01c, 1e," etc.
				} 
				$usertotal += $answer;
				$usercount++;
			}
			$useravg = $usertotal / $usercount;
			//echo "<hr/>useravg: $useravg<hr/>";
			$useroffset = $useravg - $gcv;
			//echo "<hr/>useroffset: $useroffset<hr/>";

			array_walk($individual_array['Questions'],'recenter_callback',$useroffset);
		}

		// For each SK, for each survey question, calculate the squared difference
		// between the score of the user on the question, and the average for all users
		// on that question.

		foreach($big_array as $subarea => $subarea_array) {
			foreach($subarea_array['SKs'] as $SK => $SK_array) {
				foreach($SK_array['Questions'] as $question => $answer) {
					if(!preg_match("/^_/", $question)) { 
						//echo "<HR/> skipping question $question because it's not a survey question";
						continue;
					} // Skip questions other than "01c, 1e," etc.
					if(!isset($individual_array['Questions'][$question])) {
						//echo "<HR/> skipping question $question because it's not in the individual_array";
						continue;
					} // Skip questions the user didn't answer
					$squared_diff[$SK][$question] = pow(($individual_array['Questions'][$question] - $answer),2);
					$absolute_diff[$SK][$question] = abs($individual_array['Questions'][$question] - $answer);
				}
			}
		}



		// For each SK, calculate the MSD by summing the squared differences and dividing by the number of questions

		foreach($squared_diff as $SD_SK => $SD_array) {
			foreach($SD_array as $sd) {
				//echo "<HR/>MSD[$SD_SK] += $sd";
				$MSD[$SD_SK] += $sd;
			}
			// echo "<HR/>MSD[$SD_SK] = ".$MSD[$SD_SK]." / ".count($SD_array);
			// KEL 02/08/08 -- Added rounding to 5 decimal places to save space in the cache.
			$MSD[$SD_SK] = round($MSD[$SD_SK] / count($SD_array),5);
		}
		asort($MSD); // Sort list by ascending MSD -- Best match first.

		// MAV -- Mean Absolute Value of Difference (MAV)

		foreach($absolute_diff as $SD_SK => $SD_array) {
			foreach($SD_array as $sd) {
				$MAV[$SD_SK] += $sd;
			}
			$MAV[$SD_SK] = $MAV[$SD_SK] / count($SD_array);
		}
		asort($MAV); // Sort list by ascending MAV -- Best match first.

		// SAV -- Mean Absolute Value of Difference (SAV)

		foreach($absolute_diff as $SD_SK => $SD_array) {
			foreach($SD_array as $sd) {
				$SAV[$SD_SK] += $sd;
			}
		}
		asort($SAV); // Sort list by ascending SAV -- Best match first.

		switch($mof) {
			case 'MSD':
			return $MSD;
			break;
			case 'MAV':
			return $MAV;
			break;
			case 'SAV':
			return $SAV;
			break;
		}
		// Default: MSD
		return $MSD;
	}


	/**
		* function post_process -- Run through a set of modifiers *once* on creation of a new ranking list.
		*
		* Primarily, this is used for new project randomization, since we want the newly randomized list to be
		* cached just like the original would be.
		*
		* Kristian Ljungkvist 09/19/07
		*
		**/
	function post_process($ranking_array,$individual_profile,$state_array) {
		
		$modifier_object = ModifierFactory::createModifier('NewProjectRandomizer');
		$ranking_array = $modifier_object->process($ranking_array,$individual_profile,$state_array,$this->configuration,$this->sk_summary);
		$modifier_object = ModifierFactory::createModifier('ProjectRandomizer');
		$ranking_array = $modifier_object->process($ranking_array,$individual_profile,$state_array,$this->configuration,$this->sk_summary);
		
		return $ranking_array;
	}





	/**
		* function render_results
		*
		**/
	function render_results($ranking_array,$individual_profile,$state_array,$favorites) {

		// Generate a display version of the ranking array.

		// get the list of modifiers from the recommender_configuration for this originID.
		$modifier_list = $this->configuration['ModifierList'];
		$projects_per_page = $this->configuration['MaxProjectsPerPage'];
		$page = $state_array['p'];

		// Cycle through the modifiers as a pipeline.

		foreach (split(',',$modifier_list) as $modifier) {
			//echo "instantiating $modifier...<br/>";
			// instantiate the appropriate modifier
			if($modifier != 'Paginator') {
				// Skip poginator for now, since we need to figure out how many pages long the rendered list is given the current constraints. (for page control)
				$modifier_object = ModifierFactory::createModifier($modifier);

				// Pass it the current ranking list and state
				$ranking_array = $modifier_object->process($ranking_array,$individual_profile,$state_array,$this->configuration,$this->sk_summary);
				// take the resulting ranking and pass it through to the next one.   
			}
		}

		// Get the total number of pages in the rendered ranking




		$total_pages = ceil(count($ranking_array) / $this->configuration['MaxProjectsPerPage']);



		// Now, go through the paginator:
		$modifier_object = ModifierFactory::createModifier('Paginator');

		$ranking_array = $modifier_object->process($ranking_array,$individual_profile,$state_array,$this->configuration,$this->sk_summary);


		$display_array = array();
		$cur_rank = 1;
		foreach($ranking_array as $SK => $MSD) {
			// Check for empty SK, which would only happen if there was an empty project in the array.
			// KEL 01/30/08
			if(!$SK) {
				// Notify me by email if we get an empty SK -- KEL 01/30/08
				$msg = "cur_rank = $cur_rank\n";
				$msg .= "ranking_array:\n";
				$msg .= print_r($ranking_array,true);
				$msg .= "\nIndividualID={$state_array['rid']}\n";
				$msg .= "\npage={$state_array['p']}\n";
				$msg .= "\nStateID={$state_array['sid']}\n";
				mail("kristian.ljungkvist@gmail.com","Recommender.class.php -- Empty SK",$msg);
				continue;
			}
			// escape the header fields that are prefixed with an underline, -- KEL 10/18/07
			if(strpos($SK, '_') === 0) {
				continue;
			}


			// Look up title for this SK.
			preg_match('/^([^_]+)/', $SK, $match);
			$subarea = $match[0];
/*

			$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Title'];
			if(!$cur_title) {
				// Fix for datasets generated with the dataset compiler. The Title is in the Questions Array on those datasets.
				$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['Title'];
			}
*/

			// KEL 08/29/07 -- Inserted database queries here to grab fields that we're currently not cacheing in the sk_summary.
			// We'll probably decide to cache these in the sk_summary for performance reasons later.

			$sql = "SELECT * FROM project_ideas WHERE Filename='$SK'";
			$project_idea_data = $this->DB_Connection->query($sql);


			$display_array[$cur_rank-1]['rank'] = $cur_rank;
			$display_array[$cur_rank-1]['subarea'] = $subarea;
			$display_array[$cur_rank-1]['filename'] = $SK;
			$display_array[$cur_rank-1]['title'] = $project_idea_data['Title'];

			// Store total number of pages in result set in top entry of display_array.   
			$display_array[$cur_rank-1]['total_pages'] = $total_pages;


			// We'll standardize the capitalization on these. -- KEL 
			$display_array[$cur_rank-1]['Filename'] = $SK;
			$display_array[$cur_rank-1]['Title'] = $project_idea_data['Title'];

			$display_array[$cur_rank-1]['Type'] = $project_idea_data['Type'];
			$display_array[$cur_rank-1]['DifficultyLevel_Low'] = $project_idea_data['DifficultyLevel_Low'];
			$display_array[$cur_rank-1]['DifficultyLevel_High'] = $project_idea_data['DifficultyLevel_High'];
			$display_array[$cur_rank-1]['Abstract'] = $project_idea_data['Abstract'];
			$display_array[$cur_rank-1]['Video'] = $project_idea_data['Video'];
			$display_array[$cur_rank-1]['ImgFilename_Abstract'] = $project_idea_data['ImgFilename_Abstract'];

			// Add a flag if this project has been added to favorites

			if(in_array($SK,$favorites)) {
				$display_array[$cur_rank-1]['Favorite'] = true;
			}

			$cur_rank++;
		}
		return $display_array;
	}

	/**
		* render_favorites
		*
		**/

	function render_favorites($favorites) {
		$display_array = array();
		$cur_rank = 1;
		foreach($favorites as $SK) {

			// Look up title for this SK.
			preg_match('/^([^_]+)/', $SK, $match);
			$subarea = $match[0];

			$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Title'];
			if(!$cur_title) {
				// Fix for datasets generated with the dataset compiler. The Title is in the Questions Array on those datasets.
				$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['Title'];
			}
			/*
				// Look up title for this SK.
			preg_match('/^([^_]+)/', $SK, $match);
			$subarea = $match[0];
			//echo "[$subarea],";
			//echo "[$subarea][$SK],";

			$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Title'];
			//echo "[$cur_title]<br/>";
			if(!$cur_title) {
				// Fix for datasets generated with the dataset compiler. The Title is in the Questions Array on those datasets.
				$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['Title'];
			}
			*/

			// KEL 08/29/07 -- Inserted database queries here to grab fields that we're currently not cacheing in the sk_summary.
			// We'll probably decide to cache these in the sk_summary for performance reasons later.

			$sql = "SELECT * FROM project_ideas WHERE Filename='$SK'";
			$project_idea_data = $this->DB_Connection->query($sql);

			$display_array[$cur_rank-1]['rank'] = $cur_rank;
			$display_array[$cur_rank-1]['subarea'] = $subarea;
			$display_array[$cur_rank-1]['filename'] = $SK;
			$display_array[$cur_rank-1]['title'] = $project_idea_data['Title'];

			// The following are temporarily fetched from the DB. We should probably cache these in the sk_summary data instead. -- KEL
			$display_array[$cur_rank-1]['Type'] = $project_idea_data['Type'];
			$display_array[$cur_rank-1]['DifficultyLevel_Low'] = $project_idea_data['DifficultyLevel_Low'];
			$display_array[$cur_rank-1]['DifficultyLevel_High'] = $project_idea_data['DifficultyLevel_High'];
			$display_array[$cur_rank-1]['Abstract'] = $project_idea_data['Abstract'];
			$display_array[$cur_rank-1]['ImgFilename_Abstract'] = $project_idea_data['ImgFilename_Abstract'];
			$display_array[$cur_rank-1]['Video'] = $project_idea_data['Video'];
			$display_array[$cur_rank-1]['Favorite'] = true; // It is a favorite, after all...
			$cur_rank++;
		}
		return $display_array;
	}

	/**
		* function render_interest_area
		*
		**/
	function render_interest_area($ranking_array,$individual_profile,$state_array,$favorites) {

		// Generate a display version of the ranking array, filtered by interest area.

		// get the list of modifiers from the recommender_configuration for this originID.
		$modifier_list = $this->configuration['ModifierList'];
		$projects_per_page = $this->configuration['MaxProjectsPerPage'];
		$page = $state_array['p'];

		// Add the InterestArea modifer to the pipeline
		$modifier_list = 'DifficultyLevel,InterestArea,Deduper';  // Don't do any randomization on interest areas.
	//	$modifier_list .= ',InterestArea';
		//AreaAssignment,DifficultyLevel,TimeRequired,Deduper,FirstPageNotRandom,HoneyPot,Paginator
		
		// Cycle through the modifiers as a pipeline.

		foreach (split(',',$modifier_list) as $modifier) {
			// instantiate the appropriate modifier
			if(($modifier != 'Paginator') && ($modifier != 'AreaAssignment')) {
				// Skip poginator for now, since we need to figure out how many pages long the rendered list is given the current constraints. (for page control)
				// Also skip the AreaAssignment modifier, since we want to override that with the InterestArea Modifier.
				$modifier_object = ModifierFactory::createModifier($modifier);
				

				// Pass it the current ranking list and state
				$ranking_array = $modifier_object->process($ranking_array,$individual_profile,$state_array,$this->configuration,$this->sk_summary);
				// take the resulting ranking and pass it through to the next one.   
			}
		}

		// Get the total number of pages in the rendered ranking

		$total_pages = ceil(count($ranking_array) / $this->configuration['MaxProjectsPerPage']);



		// Now, go through the paginator:
		$modifier_object = ModifierFactory::createModifier('Paginator');

		$ranking_array = $modifier_object->process($ranking_array,$individual_profile,$state_array,$this->configuration,$this->sk_summary);

		$display_array = array();
		$cur_rank = 1;
		foreach($ranking_array as $SK => $MSD) {
			// Check for empty SK, which would only happen if there was an empty project in the array.
			// escape the header fields that are prefixed with an underline, -- KEL 10/18/07
			if(strpos($SK, '_') === 0) {
				continue;
			}

			// Look up title for this SK.
			preg_match('/^([^_]+)/', $SK, $match);
			$subarea = $match[0];

			$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Title'];
			if(!$cur_title) {
				// Fix for datasets generated with the dataset compiler. The Title is in the Questions Array on those datasets.
				$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['Title'];
			}

			// KEL 08/29/07 -- Inserted database queries here to grab fields that we're currently not cacheing in the sk_summary.
			// We'll probably decide to cache these in the sk_summary for performance reasons later.

			$sql = "SELECT * FROM project_ideas WHERE Filename='$SK'";
			$project_idea_data = $this->DB_Connection->query($sql);


			$display_array[$cur_rank-1]['rank'] = $cur_rank;
			$display_array[$cur_rank-1]['subarea'] = $subarea;
			$display_array[$cur_rank-1]['filename'] = $SK;
			$display_array[$cur_rank-1]['title'] = $project_idea_data['Title'];


			// Store total number of pages in result set in top entry of display_array.   
			$display_array[$cur_rank-1]['total_pages'] = $total_pages;

			// We'll standardize the capitalization on these. -- KEL 
			$display_array[$cur_rank-1]['Filename'] = $SK;
			$display_array[$cur_rank-1]['Title'] = $project_idea_data['Title'];

			$display_array[$cur_rank-1]['Type'] = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['Type'];
			$display_array[$cur_rank-1]['DifficultyLevel_Low'] = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['DifficultyLevel_Low'];
			$display_array[$cur_rank-1]['DifficultyLevel_High'] = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['DifficultyLevel_High'];
			$display_array[$cur_rank-1]['Abstract'] = $project_idea_data['Abstract'];
			$display_array[$cur_rank-1]['Video'] = $project_idea_data['Video'];
			$display_array[$cur_rank-1]['ImgFilename_Abstract'] = $project_idea_data['ImgFilename_Abstract'];

			// Add a flag if this project has been added to favorites

			if(in_array($SK,$favorites)) {
				$display_array[$cur_rank-1]['Favorite'] = true;
			}

			$cur_rank++;
		}
		return $display_array;
	}
	
	
	/**
		* function render_interest_area_all_projects
		*
		**/
	function render_interest_area_all_projects($ranking_array,$individual_profile,$state_array,$favorites) {

		// Generate a display version of the ranking array, filtered by interest area.
		
		// For this version, we don't do any other filtering.

		
		$modifier_list = 'InterestArea';
		// Cycle through the modifiers as a pipeline.

		foreach (split(',',$modifier_list) as $modifier) {
				$modifier_object = ModifierFactory::createModifier($modifier);
				// Pass it the current ranking list and state
				$ranking_array = $modifier_object->process($ranking_array,$individual_profile,$state_array,$this->configuration,$this->sk_summary);
				// take the resulting ranking and pass it through to the next one.   
		}


		$display_array = array();
		$cur_rank = 1;
		foreach($ranking_array as $SK => $MSD) {
			// Check for empty SK, which would only happen if there was an empty project in the array.
			// escape the header fields that are prefixed with an underline, -- KEL 10/18/07
			if(strpos($SK, '_') === 0) {
				continue;
			}

			// Look up title for this SK.
			preg_match('/^([^_]+)/', $SK, $match);
			$subarea = $match[0];

			$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Title'];
			if(!$cur_title) {
				// Fix for datasets generated with the dataset compiler. The Title is in the Questions Array on those datasets.
				$cur_title = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['Title'];
			}

			// KEL 08/29/07 -- Inserted database queries here to grab fields that we're currently not cacheing in the sk_summary.
			// We'll probably decide to cache these in the sk_summary for performance reasons later.

			$sql = "SELECT * FROM project_ideas WHERE Filename='$SK'";
			$project_idea_data = $this->DB_Connection->query($sql);


			$display_array[$cur_rank-1]['rank'] = $cur_rank;
			$display_array[$cur_rank-1]['subarea'] = $subarea;
			$display_array[$cur_rank-1]['filename'] = $SK;
			$display_array[$cur_rank-1]['title'] = $project_idea_data['Title'];


			// We'll standardize the capitalization on these. -- KEL 
			$display_array[$cur_rank-1]['Filename'] = $SK;
			$display_array[$cur_rank-1]['Title'] = $project_idea_data['Title'];

			$display_array[$cur_rank-1]['Type'] = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['Type'];
			$display_array[$cur_rank-1]['DifficultyLevel_Low'] = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['DifficultyLevel_Low'];
			$display_array[$cur_rank-1]['DifficultyLevel_High'] = $this->sk_summary[$subarea]['SKs'][$SK]['Questions']['DifficultyLevel_High'];
//			$display_array[$cur_rank-1]['Abstract'] = $project_idea_data['Abstract'];
//			$display_array[$cur_rank-1]['Video'] = $project_idea_data['Video'];
//			$display_array[$cur_rank-1]['ImgFilename_Abstract'] = $project_idea_data['ImgFilename_Abstract'];

			// Add a flag if this project has been added to favorites

			if(in_array($SK,$favorites)) {
				$display_array[$cur_rank-1]['Favorite'] = true;
			}

			$cur_rank++;
		}
		return $display_array;
	}

	/**
		* function get_first_recommendation -- returns the top project that would be displayed for this user, which in many cases
		* will differ from the top ranked project due to interestarea restrictions, difficulty level, and time required.
		*
		* Basically, this method runs through all the standard filters and modifiers except the pagination modifier, and 
		* Returns the first entry in the resulting list.
		*
		* Primarily, this is used for logging the FirstRecommendation in the recommender_action table.
		*
		* Kristian Ljungkvist 10/09/07
		*
		**/  
	function get_first_recommendation($ranking_array,$individual_profile,$state_array,$favorites) {
		// get the list of modifiers from the recommender_configuration for this originID.
		$modifier_list = $this->configuration['ModifierList'];
		$projects_per_page = $this->configuration['MaxProjectsPerPage'];
		$page = $state_array['p'];

		// Cycle through the modifiers as a pipeline.

		foreach (split(',',$modifier_list) as $modifier) {
			//echo "instantiating $modifier...<br/>";
			// instantiate the appropriate modifier
			if($Modifier != 'Paginator') {
				$modifier_object = ModifierFactory::createModifier($modifier);
				// Pass it the current ranking list and state
				$ranking_array = $modifier_object->process($ranking_array,$individual_profile,$state_array,$this->configuration,$this->sk_summary);
				// take the resulting ranking and pass it through to the next one.   
			}
		}
		return key($ranking_array);

	}
	/**
		* get_title_of_sk
		*
		**/

	function get_title_of_sk($SK) {
		$sql = "SELECT * FROM project_ideas WHERE Filename='$SK'";
		$project_idea_data = $this->DB_Connection->query($sql);
		return $project_idea_data['Title'];
	}

	/**
		* get_solt_details_of_sk
		*
		* Eleboration on get_title_of_sk to get subareacode, etc.
		**/

	function get_solt_details_of_sk($SK) {
		$sql = "SELECT * FROM project_ideas WHERE Filename='$SK'";
		$project_idea_data = $this->DB_Connection->query($sql);
		return $project_idea_data;
	}


	/**
		* get_msd_of_sk
		*
		**/

	function get_MSD_of_sk($SK,$individual_state,$state_array) {
		$stateID = $state_array['sid'];

		// First, find the most recent individual-based ranking for this individual.

		$mrir = $this->get_most_recent_individual_ranking($individual_state);
		//	echo "<hr/>mrir:<br/>";
		//	print_r($mrir);
		//	echo "<hr/>";

		// Find the record in the corresponding ranking list for SK.
		$MSD = $mrir[$SK];
		return($MSD);
	}

	/**
		* get_most_recent_individual_ranking($individual_state)
		*
		* @return array: most recent individual ranking
		* @author Kristian Ljungkvist
		**/
	function get_most_recent_individual_ranking($individual_state) {
		// Loop through the states and identify the individual-sourced
		// ranking with the highest stateID.
		$i= 1;
		$most_recent_ind_ranking = 1; // default, since we know the first ranking is based on the ind.
		foreach($individual_state as $cur_state) {
			//echo "$i: cur_state:".print_r($cur_state)."<hr/>";
			//echo "index: $i:cur_state::ranking::Source = ".$cur_state['ranking']['_Source']."<br/>";
			if(!$cur_state['ranking']) {continue;}
			if($cur_state['ranking']['_Source'] =='Individual') {
				$most_recent_ind_ranking = $i;
				//echo "most_recent_ind_ranking: $most_recent_ind_ranking<br/>";
			}
			$i++;
		}
		return $individual_state[$most_recent_ind_ranking]['ranking'];
	}

	/**
		* get_most_recent_individual_ranking_id($individual_state)
		*
		* @return int: most recent individual ranking ID (stateID in cache)
		* @author Kristian Ljungkvist
		**/
	function get_most_recent_individual_ranking_id($individual_state) {
		// Loop through the states and identify the individual-sourced
		// ranking with the highest stateID.
		$i= 1;
		$most_recent_ind_ranking = 1; // default, since we know the first ranking is based on the ind.
		foreach($individual_state as $cur_state) {
			//echo "$i: cur_state:".print_r($cur_state)."<hr/>";
			//echo "index: $i:cur_state::ranking::Source = ".$cur_state['ranking']['_Source']."<br/>";
			if(!$cur_state['ranking']) {continue;}
			if($cur_state['ranking']['_Source'] =='Individual') {
				$most_recent_ind_ranking = $i;
				//echo "most_recent_ind_ranking: $most_recent_ind_ranking<br/>";
			}
			$i++;
		}
		return $most_recent_ind_ranking;
	}

	/**
		* get_cached_solt_ranking_id($solt_sk, $individual_state)
		*
		* @return int: stateID of cached ranking for this project (if it's in the cache)
		* @author Kristian Ljungkvist
		**/
	function get_cached_solt_ranking_id($solt_sk,$individual_state) {
		$cached_solt_ranking_id = -1; // -1 means no match, in this context.
		$i=1;
		foreach($individual_state as $cur_state) {
			if(!$cur_state['ranking']) {continue;}
			if(($cur_state['ranking']['_Source'] =='Project') && ($cur_state['ranking']['_SourceProfile'] == $solt_sk)) {
				$cached_solt_ranking_id = $i;
			}
			$i++;
		}
		return $cached_solt_ranking_id;	
	}

	/**
		* get_page_indicator
		*
		**/
	function get_page_indicator($display_array,$state_array) {
		$total_pages = $display_array[1]['total_pages'];
		$current_page = $state_array['p'];

		// Figure out which page numbers to display. Return an array 


		// First, figure out if we should display the '<' and '>' buttons.
		if($current_page == 1) {
			$p_i['Prev'] = 0;
		} else {
			$p_i['Prev'] = 1;
		}

		if($current_page +1 > $total_pages) {
			$p_i['Next'] = 0;
		} else {
			$p_i['Next'] = 1;
		}

		// Now, figure out the range of numbers to display.
		// This should be 11 numbers.

		// If current_page < 7, 1-11. >=7, current_page - 5 through current_page + 5 (unless total_pages is less.)

		if($current_page < 7) {
			$pages = range(1,max((min(11,$total_pages)),1));  // The max function is there to handle the case where total_pages is zero (KEL 07/03/08)
		} else {
			if(($current_page + 5) < $total_pages) {
				$pages = range(($current_page - 5),($current_page + 5));
			} else {
				$pages = range(($current_page -5), $total_pages);
			}
		}

		$p_i['Pages'] = $pages;


		return $p_i;
	}

	/**
		* recommendation_summary
		*
		* @param ranking_array current ranking
		* @param max_areas_to_include: hard limit (if non-zero) of how many areas to include
		* @param msd_limit: limit, max MSD of areas to include. If any area has a median higher than this, 
		*		  it is not included in the results.
		* @return array containing a sorted, possibly restricted list of median MSDs per interest area.
		* @author Kristian Ljungkvist
		**/
	function recommendation_summary($ranking_array,$min_areas_to_include,$max_areas_to_include,$msd_limit){

		foreach($ranking_array as $SK => $MSD) {
			if(strpos($SK, '_') === 0) {
				continue;
			}


			//	Build array of subarea,MSD for all subareas in ranking:
			//	Chem => array(0.23,0.24,0.34)
			//	Bio => array(0.34,0.55,0.67)

			// Extract the sub area
			preg_match('/^([^_]+)/', $SK, $match);
			$subarea = $match[0];
			if($subarea == 'HoneyPot') {
				continue;
			}
			$msd_by_area[$subarea][]=$MSD;

		}
		// Compute the median msd for each area
		foreach($msd_by_area as $area => $msd_list) {
			if($area) {
				$median_msd_by_area[$area] = $msd_list[floor(count($msd_list)/2)];
			}
		}

		// Now sort the areas in increasing median msd order.
		asort($median_msd_by_area);
		// First, if msd_limit is set, exclude any areas with median msd higher than that number

		if($msd_limit) {
			foreach($median_msd_by_area as $area => $median_msd) {
				if($median_msd <= $msd_limit) {
					$restricted_list[$area] = $median_msd;
				}
			}
			if(count($restricted_list) > $min_areas_to_include) {
				$median_msd_by_area = $restricted_list;
			}
		}

		// Secondly, if max_areas_to_include is set, place a hard-limit on the number of items in the list.
		if($max_areas_to_include) {
			$median_msd_by_area = array_slice($median_msd_by_area, 0, $max_areas_to_include);
		}

		// Look up interest area titles, etc. from project_ideas table.
		$cur_rank = 0;
		foreach($median_msd_by_area as $area => $median_msd) {
			$sql = "SELECT * FROM project_ideas WHERE SubAreaCode='$area' LIMIT 1";
			$project_idea_area_data = $this->DB_Connection->query($sql);

			$display_array[$cur_rank]['subareacode'] = $project_idea_area_data['SubAreaCode'];
			$display_array[$cur_rank]['subarea'] = $project_idea_area_data['SubArea'];
			$display_array[$cur_rank]['area'] = $project_idea_area_data['Area'];
			$display_array[$cur_rank]['subarea_median_msd'] = $median_msd;
			$cur_rank++;
		}
		// return the displayable list, limited perhaps by length and max MSD.
		return($display_array);
	}
}
?>