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site/jpgraph/Examples/example16.6.php 1.44 KB
8ec98c9f   Guillaume   MAJ
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  <?php // content="text/plain; charset=utf-8"
  require_once ('jpgraph/jpgraph.php');
  require_once ('jpgraph/jpgraph_scatter.php');
  require_once ('jpgraph/jpgraph_line.php');
  require_once ('jpgraph/jpgraph_utils.inc.php');
  
  // Create some "fake" regression data
  $datay = array();
  $datax = array();
  $a= 3.2;
  $b= 2.5;
  for($x=0; $x < 20; ++$x) {
      $datax[$x] = $x;
      $datay[$x] = $a + $b*$x + rand(-20,20);
  }
  
  $lr = new LinearRegression($datax, $datay);
  list( $stderr, $corr ) = $lr->GetStat();
  list( $xd, $yd ) = $lr->GetY(0,19);
  
  // Create the graph
  $graph = new Graph(300,250);
  $graph->clearTheme();
  $graph->SetScale('linlin');
  
  // Setup title
  $graph->title->Set("Linear regression");
  $graph->title->SetFont(FF_ARIAL,FS_BOLD,14);
  
  $graph->subtitle->Set('(stderr='.sprintf('%.2f',$stderr).', corr='.sprintf('%.2f',$corr).')');
  $graph->subtitle->SetFont(FF_ARIAL,FS_NORMAL,12);
  
  // make sure that the X-axis is always at the
  // bottom at the plot and not just at Y=0 which is
  // the default position
  $graph->xaxis->SetPos('min');
  
  // Create the scatter plot with some nice colors
  $sp1 = new ScatterPlot($datay,$datax);
  $sp1->mark->SetType(MARK_FILLEDCIRCLE);
  $sp1->mark->SetFillColor("red");
  $sp1->SetColor("blue");
  $sp1->SetWeight(3);
  $sp1->mark->SetWidth(4);
  
  // Create the regression line
  $lplot = new LinePlot($yd);
  $lplot->SetWeight(2);
  $lplot->SetColor('navy');
  
  // Add the pltos to the line
  $graph->Add($sp1);
  $graph->Add($lplot);
  
  // ... and stroke
  $graph->Stroke();
  
  ?>