ggorlen/matrixmult.php

## matrixmult.php
<?php
  if (isset($_GET['source'])) {
    highlight_file($_SERVER['SCRIPT_FILENAME']);
    exit;
  }
?>

<!DOCTYPE html>
<html lang='en'>
  <head>
    <title>Matrix multiplier</title>
    <style>
      body {
        font-family: monospace;
        font-size: 16px;
      }
      input {
        font-family: monospace;
      }
      table {
        border-collapse: collapse;
      }
      td {
        border: 1px solid #888;
        text-align: right;
        padding: 10px;
      }
    </style>
  </head>
  <body>
    <div style="margin: 10px; width: 300px;">
      <h2>Matrix multiplier</h2>
      <p>
        Matrix contents delimited by spaces and line breaks.  Ex:
        <br>
        <br>4 5 6&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5 8
        <br>8 -1 3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3 5
        <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2 9
      </p>
      <form id="input" method=POST action="matrixmult.php">
        <textarea autofocus rows=5 cols=10 name="matrix1"><?php
          if (count($_POST) === 2 ||
              isset($_POST['matrix1'])) {
            print trim($_POST['matrix1']);
          }
          ?></textarea>
        <textarea rows=5 cols=10 name="matrix2"><?php
          if (count($_POST) === 2 ||
              isset($_POST['matrix2'])) {
            print trim($_POST['matrix2']);
          }
          ?></textarea>
        <br>
        <input type="submit">
      </form>
      <br>

      <?php
        (function() {
          /* matrix multiplier
           *
           * http://www.purplemath.com/modules/mtrxmult2.htm
           */


          // abort if no data submitted
          if (!count($_POST) === 2 ||
              !isset($_POST['matrix1']) ||
              !isset($_POST['matrix2'])) return;

          // grab input data and parse
          $matrix1Raw = explode("\n", trim($_POST['matrix1']));
          $matrix2Raw = explode("\n", trim($_POST['matrix2']));
          $matrix1 = [];
          $matrix2 = [];
          $result = [];

          for ($i = 0; $i < sizeof($matrix1Raw); $i++) {
            array_push($matrix1,
              array_map('floatval', explode(" ", trim($matrix1Raw[$i])))
            );
          }

          for ($i = 0; $i < sizeof($matrix2Raw); $i++) {
            array_push($matrix2,
              array_map('floatval', explode(" ", trim($matrix2Raw[$i])))
            );
          }
          // validation check
          if (sizeof($matrix1[0]) !== sizeof($matrix2)) {
            print "<em>Error: number of columns in matrix A
                   must equal the number of rows in matrix B.</em";
            return;
          }

          // calculate product of matrices
          for ($row = 0; $row < sizeof($matrix1); $row++) {
            for ($col = 0; $col < sizeof($matrix2[0]); $col++) {
              $total = 0;
              for ($i = 0; $i < sizeof($matrix2); $i++) {
                if (!isset($matrix2[$i][$col]) || !isset($matrix1[$row][$i])) {
                  print "<em>Error: invalid input.</em>";
                  return;
                }
                $total += $matrix2[$i][$col] * $matrix1[$row][$i];
              }
              $result[$row][$col] = $total;
            }
          }

          // print result matrix
          print "<table>";
          for ($i = 0; $i < sizeof($result); $i++) {
            print "<tr>";
            for ($j = 0; $j < sizeof($result[$i]); $j++) {
              print "<td>" . $result[$i][$j] . "</td>";
            }
            print "</tr>";
          }
          print "</table>";
        })();
      ?>
    </div>
  </body>
</html>
	<?php
	if (isset($_GET['source'])) {
	highlight_file($_SERVER['SCRIPT_FILENAME']);
	exit;
	}
	?>

	<!DOCTYPE html>
	<html lang='en'>
	<head>
	<title>Matrix multiplier</title>
	<style>
	body {
	font-family: monospace;
	font-size: 16px;
	}
	input {
	font-family: monospace;
	}
	table {
	border-collapse: collapse;
	}
	td {
	border: 1px solid #888;
	text-align: right;
	padding: 10px;
	}
	</style>
	</head>
	<body>
	<div style="margin: 10px; width: 300px;">
	<h2>Matrix multiplier</h2>
	<p>
	Matrix contents delimited by spaces and line breaks. Ex:
	<br>
	<br>4 5 6      5 8
	<br>8 -1 3     3 5
	<br>           2 9
	</p>
	<form id="input" method=POST action="matrixmult.php">
	<textarea autofocus rows=5 cols=10 name="matrix1"><?php
	if (count($_POST) === 2 \|\|
	isset($_POST['matrix1'])) {
	print trim($_POST['matrix1']);
	}
	?></textarea>
	<textarea rows=5 cols=10 name="matrix2"><?php
	if (count($_POST) === 2 \|\|
	isset($_POST['matrix2'])) {
	print trim($_POST['matrix2']);
	}
	?></textarea>
	<br>
	<input type="submit">
	</form>
	<br>

	<?php
	(function() {
	/* matrix multiplier
	*
	* http://www.purplemath.com/modules/mtrxmult2.htm
	*/


	// abort if no data submitted
	if (!count($_POST) === 2 \|\|
	!isset($_POST['matrix1']) \|\|
	!isset($_POST['matrix2'])) return;

	// grab input data and parse
	$matrix1Raw = explode("\n", trim($_POST['matrix1']));
	$matrix2Raw = explode("\n", trim($_POST['matrix2']));
	$matrix1 = [];
	$matrix2 = [];
	$result = [];

	for ($i = 0; $i < sizeof($matrix1Raw); $i++) {
	array_push($matrix1,
	array_map('floatval', explode(" ", trim($matrix1Raw[$i])))
	);
	}

	for ($i = 0; $i < sizeof($matrix2Raw); $i++) {
	array_push($matrix2,
	array_map('floatval', explode(" ", trim($matrix2Raw[$i])))
	);
	}
	// validation check
	if (sizeof($matrix1[0]) !== sizeof($matrix2)) {
	print "<em>Error: number of columns in matrix A
	must equal the number of rows in matrix B.</em";
	return;
	}

	// calculate product of matrices
	for ($row = 0; $row < sizeof($matrix1); $row++) {
	for ($col = 0; $col < sizeof($matrix2[0]); $col++) {
	$total = 0;
	for ($i = 0; $i < sizeof($matrix2); $i++) {
	if (!isset($matrix2[$i][$col]) \|\| !isset($matrix1[$row][$i])) {
	print "<em>Error: invalid input.</em>";
	return;
	}
	$total += $matrix2[$i][$col] * $matrix1[$row][$i];
	}
	$result[$row][$col] = $total;
	}
	}

	// print result matrix
	print "<table>";
	for ($i = 0; $i < sizeof($result); $i++) {
	print "<tr>";
	for ($j = 0; $j < sizeof($result[$i]); $j++) {
	print "<td>" . $result[$i][$j] . "</td>";
	}
	print "</tr>";
	}
	print "</table>";
	})();
	?>
	</div>
	</body>
	</html>