Simple Linear System Solver

solver.html

<!--
Code by the Illinois VLSI CAD teaching staff.
Released under the University of Illinois/NCSA Open Source License
-->

<div class="alert alert-info">
<p>
Fill in the matrix A and the vector b and click "Solve!".
</p>
</div>
<div class="row offset1">
  <div class="span4">
		<b>Input matrix A</b>
		<br>
<textarea rows="5" id="matrixA" style="width:250px;">
1 2
3 4
</textarea>
	</div>
</div>
<div class="row offset1">
	<div class="span4">
		<b>Input vector b</b>
		<br>
<textarea rows ="5" id="vectorB" style="width:250px;">
17
39
</textarea>
	</div>
</div>
<div class="row offset1">
	<div class="span4">
		<b>Solution vector x</b>
		<br>
<textarea readonly rows ="5" id="vectorX" style="width:250px;">
</textarea>
	</div>
</div>

<div class="row offset1">
	<div class="span4">
	<p>
	  <button class="btn btn-primary" type="button" id="solveButton">Solve!</button>
	</p>
        <br>
        <br>
        Solver uses the <a href="http://www.numericjs.com/documentation.html">numerical.js</a> library by Sebastien Loisel.
	</div>
</div>

<!-- Serve this through a https:// or else Chrome will complain -->
<!-- Ideally, I don't want to load jQuery since Coursera has its own version. However, Coursera chooses to load its script at the end so $(...) isn't available when we need it. -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script src="https://spark-public.s3.amazonaws.com/vlsicad/javascript_tools/numeric-1.2.6.min.js"></script>
<script>

// Create namespace to be safe - don't want any collisions with Coursera's code
var edu = {
	illinois: {
		vlsicad: (function() {
			var solveEquation = function() {
				var matrixA = matrixToArray($("#matrixA").val());
				var vectorB = columnToArray($("#vectorB").val());
				var solution = numeric.solve(matrixA, vectorB);
				displaySolution(solution);
				return solution; // For checking in the debugger
			}

			var matrixToArray = function(matrixString) {
				var rows = matrixString.split("\n");
				var filteredRows = rows.filter(function(e) { return !isBlank(e) });
				return filteredRows.map(rowToArray);
			}

			var rowToArray = function(rowString) {
				return rowString.split(/\s+/).map(parseFloat);
			}

			var columnToArray = function(columnString) {
				var rows = columnString.split("\n");
				var filteredRows = rows.filter(function(e) { return !isBlank(e)});
				return filteredRows.map(parseFloat);
			}

			var displaySolution = function(solutionArray) {
				var stringToDisplay = "";
				solutionArray.forEach(function(e) {
					stringToDisplay += e.toFixed(3) + "\n";
				});
				$("#vectorX").val(stringToDisplay);
			}

			var isBlank = function(string) {
				return (!string || /^\s*$/.test(string));
			}

			// Only expose the solveEquation function
			return {
				solveEquation: solveEquation
			};
		})()
	}
}

$(function() {
	$('#solveButton').bind('click', edu.illinois.vlsicad.solveEquation);
});

</script>