dergachev/pi.php

## pi.php
<!DOCTYPE html>
<html>
    <head>
    	<link type='text/css' rel='stylesheet' href='style.css'/>
		<title>Finding Pi</title>
	</head>
	<body>
	<?php

	echo "Here is PHP, echoing Pi:" . " " . M_PI . "<br  /><br />";

  echo "We will use a circle with radius 1, inside a 2x2 square to calculate Pi. <br />
        We will pick random points in the square and see if they also land in the circle. <br />
        Then we will calcuate the ratio and multiply by 4 to estimate Pi.<br /><br />";

  // Arrays to hold counts for when a point is in or out of the circle.
  // the square array really just counts how many iterations we do.
  $incircle = 0;
  $insquare = 0;


  // for loop iterates as many times as we like. The higher the iteration, the more accurate the end result.
  for ($i = 0; $i<=10000000; $i++){

    // x co-ordinate generator
    $xgen = (mt_rand()*2) / mt_getrandmax();
    $x = $xgen-1;

    // y co-ordinate generator
    $ygen = (mt_rand()*2) / mt_getrandmax();
    $y = $ygen-1;

    // if statement determines whether the point is in or out of the circle.
    if (sqrt($x*$x + $y*$y) <= 1) {
      $incircle++;
    }

    $insquare++;
  }

  echo "In the circle: " . $incircle . "<br />";
  echo "In the square: " . $insquare . "<br />";
  echo "Ratio: " . $incircle/$insquare . "<br />";
  echo "Our Pi estimate is " . $incircle*4/$insquare;

	?>
    </body>
</html>
	<!DOCTYPE html>
	<html>
	<head>
	<link type='text/css' rel='stylesheet' href='style.css'/>
	<title>Finding Pi</title>
	</head>
	<body>
	<?php

	echo "Here is PHP, echoing Pi:" . " " . M_PI . "<br /><br />";

	echo "We will use a circle with radius 1, inside a 2x2 square to calculate Pi. <br />
	We will pick random points in the square and see if they also land in the circle. <br />
	Then we will calcuate the ratio and multiply by 4 to estimate Pi.<br /><br />";

	// Arrays to hold counts for when a point is in or out of the circle.
	// the square array really just counts how many iterations we do.
	$incircle = 0;
	$insquare = 0;


	// for loop iterates as many times as we like. The higher the iteration, the more accurate the end result.
	for ($i = 0; $i<=10000000; $i++){

	// x co-ordinate generator
	$xgen = (mt_rand()*2) / mt_getrandmax();
	$x = $xgen-1;

	// y co-ordinate generator
	$ygen = (mt_rand()*2) / mt_getrandmax();
	$y = $ygen-1;

	// if statement determines whether the point is in or out of the circle.
	if (sqrt($x$x + $y$y) <= 1) {
	$incircle++;
	}

	$insquare++;
	}

	echo "In the circle: " . $incircle . "<br />";
	echo "In the square: " . $insquare . "<br />";
	echo "Ratio: " . $incircle/$insquare . "<br />";
	echo "Our Pi estimate is " . $incircle*4/$insquare;

	?>
	</body>
	</html>