function cluster($k){

$db = new db();

$user_dao = new User_dao();

$user = $user_dao->getAll(); //get data user

//create graph

$graph = new Graph(700,600);

//set graph

$graph->SetScale("linlin");

$graph->img->SetMargin(70,50,50,50);

//$graph->SetShadow();

$graph->title->Set("Friends Twitter Clustering");

$graph->title->SetFont(FF_ARIAL,FS_NORMAL,14);

$graph->title->SetFont(FF_FONT1,FS_BOLD);

$graph->title->SetMargin(10);

$userx = $user->name;

$graph->subtitle->Set("User: ".$userx." (".$k." Kluster)");

$graph->subtitle->SetFont(FF_FONT1,FS_BOLD);

//$graph->yaxis->scale->SetAutoMax(1); //untuk seting max nilai y

//$graph->xaxis->scale->SetAutoMax(1); //untuk seting max nilai x

//

$following_dao = new Following_dao();

/*

$data = $following_dao->get();

$x = array();

$y = array();

for($i=0; $i<count($data); $i++){

$x[]=$data[$i][0];

$y[]=$data[$i][1];

}

//format scatterplots data

$scatterplots = new ScatterPlot($y, $x); // (Data)

$scatterplots->mark->SetType(MARK_FILLEDCIRCLE);

$scatterplots->mark->SetFillColor("blue");

$scatterplots->mark->SetWidth(4);

*/

$warna = array("blue","orange","green","purple","maroon","pink","cyan","violet","lime","fuchsia","maroon","olive","navy","purple",

"chocolate","coral","lightblue","orchid","skyblue","yellow","","","","","","","","","","","","","","","","","","",""); //warna untuk cluster

//data cluster

for($i=0; $i<$k; $i++){

$x = array();

$y = array();

$data = $following_dao->getByCluster($i+1);

//var_dump($data);

for($j=0; $j<count($data); $j++){

$x[]=$data[$j][0];

$y[]=$data[$j][1];

}

//var_dump($x);

$scatterplots[$i] = new ScatterPlot($y,$x);

$scatterplots[$i]->mark->SetType(MARK_FILLEDCIRCLE);

if($warna[$i]==""){$warna[$i]="gold";}

$scatterplots[$i]->mark->SetFillColor($warna[$i]);

$scatterplots[$i]->mark->SetWidth(3);

$graph->Add($scatterplots[$i]);

}

// data centroid

$centroid_dao = new Centroid_dao();

$data2 = $centroid_dao->get();

$x2 = array();

$y2 = array();

for($i=0; $i<count($data2); $i++){

$x2[]=$data2[$i][0];

$y2[]=$data2[$i][1];

}

$centroids = new ScatterPlot($y2, $x2); // (Centroids)

$centroids->mark->SetType(MARK_CROSS);

$centroids->mark->SetFillColor("red");

$centroids->mark->SetColor("red");

$centroids->mark->SetWeight(10);

$centroids->mark->SetWidth(50);

$centroids->value->SetColor("black");

// Add plots to graph.

$graph->Add($centroids);

//$graph->Add($scatterplots);

$graph->xaxis->title->Set('Followers Similarity');

$graph->yaxis->title->Set('Followings Similarity');

$graph->yaxis->title->SetMargin(10);

// Display graph

$graph->Stroke();

}