public function testComplexCase()
{
$r = new LinearRegression(Dataset::fromArray([0.5, 1, 4, -1]));
$this->assertSame(-0.15, $r->slope());
$this->assertSame(1.35, $r->intercept());
$this->assertSame(0.0, $r(9));
}
// content="text/plain; charset=utf-8"
require_once '../../vendor/autoload.php';
require_once 'jpgraph/jpgraph_scatter.php';
use Amenadiel\JpGraph\Graph;
use Amenadiel\JpGraph\Plot;
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\Graph(300, 250);
$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
$graph->xaxis->SetPos('min');
// Create the scatter plot with some nice colors
public function init($title, $xdata, $ydata, $width = 350, $height = 320)
{
// 1. Setup some member variables
//$graph_width=$width;
//$graph_height=$height;
//$graph_title=$title;
// 2. We'll need a graph object
$this->graph = new \Graph($width, $height);
// 3. Set some random values
$this->graph->SetScale("textlin");
$this->graph->title->Set($title);
// 4. Build the linear regression class
$linreg = new \LinearRegression($xdata, $ydata);
// 4.1 Get the basic linear regression statistics
list($stderr, $corr) = $linreg->GetStat();
list($xd, $yd) = $linreg->GetY(1, count($xdata));
list($b, $m) = $linreg->GetAB();
// 4.2 Create the regression line
$lplot = new \LinePlot($yd);
$lplot->SetWeight(3);
$lplot->SetColor('navy');
// 5. Calculate regression and goal statistics
//$mp = CakeNumber::precision($m, 0);
//$bp = CakeNumber::precision($b, 0);
// 5.1 y=mx+b
//$s = "y = ".CakeNumber::precision($m,$p)."x + $bp";
$s = "y = {$m} x + {$b}";
$txt = new \Text($s);
$txt->SetPos($this->left_margin, $this->stats_base_y);
// Set color and font for the text
$txt->SetColor('red');
$txt->SetFont(FF_FONT2, FS_BOLD);
$this->graph->AddText($txt);
// 4.2 present amount
//$present_amt = end($this->ydata);
//App::uses("CakeNumber", "Utility");
//$txt = new Text("p=" . CakeNumber::precision($present_amt,0));
//$txt->SetPos($this->left_margin, $this->stats_base_y+$this->stats_line_ht);
//$this->graph->AddText($txt);
// 4.3 the goal
//$delta = $this->goal - $present_amt;
//$deltaP = $delta/$m;
//$deltaP = CakeNumber::precision($deltaP, 1);
//$s = "g = $this->goal";
//$txt = new Text($s);
//$txt->SetPos($this->left_margin, $this->stats_base_y+$this->stats_line_ht*2);
//$this->graph->AddText($txt);
//$s = "t = $deltaP";
//$txt = new Text($s);
//$txt->SetPos($this->left_margin, $this->stats_base_y+$this->stats_line_ht*3);
//$this->graph->AddText($txt);
$this->graph->Add($lplot);
//$this->graph->legend->SetPos(0.5,0.98,'center','bottom');
//$this->graph->legend->SetAbsPos(0,0);
//$this->graph->yaxis->SetColor('red');// this works here, but not earlier
//$this->graph->xaxis->SetColor('blue');
//$this->graph->SetAxisLabelBackground(1,'red');
//$this->graph->SetAxisLabelBackground(2,'green');
//$this->graph->SetBackgroundCFlag(2,BGIMG_FILLPLOT,100); // no discernable effect
//$this->graph->SetBackgroundGradient('navy','silver',2,BGRAD_FRAME); // no discernable effect
//$this->graph->SetBox(true, array(80,80,80), 10);
//$this->graph->SetBox();
//$this->graph->SetFrame(true,'darkblue',20);
//$this->graph->SetFrameBevel(20,true,'black');
//$this->graph->SetMarginColor('silver');
//$this->graph->SetMargin($this->left_margin,50,50,50); // left, right, top, bottom
//$this->graph->SetMargin(50,50,50,0); // left, right, top, bottom
}
