twedl/README.md

## README.md

      
    Raw
  

              README.md
            
          
    If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000.
I start with the example of N=150.  The algorithm:

Set sum to 0.
Loop from n=1 to N.

if n is divisible by 3 or 5, add n to sum.


Things to consider:

Do I want to match the algorithm perfectly? Then there wouldn't be different colours or levels, just "Add" or "Ignore".
Or do I want it to point out problems? E.g., if you split up Step 2.1 into two steps, "Check %3==0" and "Check %5==0", then you'll add multiples of 15 twice, hence the red colour for 15, 30, 45, etc.
A cooler algorithm might be to loop through multiples of 3 (instead of 1 to N) and 5 directly, add them, then subtract multiples of (3*5), like set addition and subtraction. But that's not the easiest solution, which I think should be my goal.
The way D3 handles data is more complicated than it seems.

A transition applied to a dataset will affect all elements at the same time, except I want to show a loop.
So the "var i = test.shift()" on line 92 is a bit hacky, but will loop through the elements of a copied version of the dataset.
Then it redraws every line for every time through the loop.
And after one loop is finished, it calls a transition on the transition recursively.
I also don't want it to stall on the last element, so I add an invisible line to the end, because the number of loops is determined by the number of elements.


Some resources: Project Euler Problem #1, Help with SVG Labels, and many examples from Mike Bostock.

  
## index.html
<!DOCTYPE html>
<meta charset="utf-8">
<style>

.line {
  stroke: #000;
  stroke-width: 1.5px;
  stroke-linecap: round;
}

</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/topojson.v1.min.js"></script>
<script>

var margin = {top: 230, right: 100, bottom: 80, left: 60},
    width = 960 - margin.left - margin.right,
    height = 350 - margin.top - margin.bottom;

var n = 150,
    array = d3.range(1,n+1),
    test = array,
    e = [],
    sum = 0;

for (var i=0; i<n; i++) {
    e.push({num: array[i], on: 0, is3: 0, is5: 0, acti: 1, vis: 1});
}
    e.push({num: n+1, on: 0, is3: 0, is5:0, acti: 0, vis: 0});
    test = e.slice();

var x = d3.scale.ordinal()
    .domain(d3.range(0,n+1))
    .rangePoints([0, width]);

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var line = svg.append("g")
    .attr("class", "line")
    .selectAll("line")
    .data(e)
    .enter().append("line")
    .attr("transform", transform)
    .attr("y2", function(d) {
        return -height*d.vis;
    });

var text = svg.append("g")
    .attr("class", "label")
    .selectAll("text")
    .data([3,5,15])
    .enter().append("text")
    .attr("x", function(d) { return "" + x(n) + ""; })
    .attr("y", function(d) { return -height*(0.4+(+(d%3==0)) + 2*(+(d%5==0))); })
    .style("fill", function(d) {
        return "rgb(" + 255*(+(d%3==0))*(+(d%5==0)) + ","
                + 255*(+(d%3==0))*(1-+(d%5==0)) + ","
                + 255*(1-+(d%3==0))*(+(d%5==0)) + ")";
    })
    .text(function(d) { return "x%" + d + "==0"; })
    .attr("font-family", "sans-serif")
    .attr("font-size", "20px");

var xtext = svg.append("g")
        .selectAll("text")
        .data([""])
        .enter().append("text")
        .attr("x", width/2+32)
        .attr("y", height/2+20)
        .text("x = 0")
        .attr("font-family", "sans-serif")
        .attr("font-size", "20px");

var sumtext = svg.append("g")
        .selectAll("text")
        .data([""])
        .enter().append("text")
        .attr("x", width/2)
        .attr("y", height/2+40)
        .text("Sum = 0")
        .attr("font-family", "sans-serif")
        .attr("font-size", "20px");

var transition = d3.transition()
    .duration(100)
    .each("start", function start() {
        var i = test.shift();
        if (i.num<n+1) {
            e[i.num-1].on = 1;
        }
        if (i.num%3==0) {
            e[i.num-1].is3 = 1;
        }
        if (i.num%5==0) {
            e[i.num-1].is5 = 1;
        }
        if (i.num%5==0 || i.num%3==0) {
            sum+=i.num;
        }
        if (i.num-1>0) {
            e[i.num-2].on = 0;
            e[i.num-2].acti = e[i.num-2].is3 + e[i.num-2].is5;
        }
        transition.each(function() {
            line.transition()
                .attr("transform", transform)
                .style("stroke", function(d) {
                    if (d.acti) {
                        return "rgb(" + 255*(1-d.on)*(d.is3)*(d.is5) + ","
                            + 255*(1-d.on)*(d.is3)*(1-d.is5) + ","
                            + 255*(1-d.on)*(1-d.is3)*(d.is5) + ")";
                    }
                    else if (!d.acti) {
                        return "rgb(221,221,221)";
                    }
                });
            xtext.transition()
                .text(function(d) {
                    if (i.num<=n) {
                        console.log(d);
                        return "x = " + i.num;
                }
                });
            sumtext.transition()
                .text(function(d) {
                    console.log(d);
                    return "Sum = " + sum;
                });
        });
        if (test.length) {
            transition = transition.transition().each("start", start);
        }
    });

function transform(d, i) {
    return "translate(" + x(i) + "," + height*(-d.is3-d.is5*2)*d.vis + ")";
}

</script>
</body>

## thumbnail.png

      
    Raw
  

              thumbnail.png
	<!DOCTYPE html>
	<meta charset="utf-8">
	<style>

	.line {
	stroke: #000;
	stroke-width: 1.5px;
	stroke-linecap: round;
	}

	</style>
	<body>
	<script src="http://d3js.org/d3.v3.min.js"></script>
	<script src="http://d3js.org/topojson.v1.min.js"></script>
	<script>

	var margin = {top: 230, right: 100, bottom: 80, left: 60},
	width = 960 - margin.left - margin.right,
	height = 350 - margin.top - margin.bottom;

	var n = 150,
	array = d3.range(1,n+1),
	test = array,
	e = [],
	sum = 0;

	for (var i=0; i<n; i++) {
	e.push({num: array[i], on: 0, is3: 0, is5: 0, acti: 1, vis: 1});
	}
	e.push({num: n+1, on: 0, is3: 0, is5:0, acti: 0, vis: 0});
	test = e.slice();

	var x = d3.scale.ordinal()
	.domain(d3.range(0,n+1))
	.rangePoints([0, width]);

	var svg = d3.select("body").append("svg")
	.attr("width", width + margin.left + margin.right)
	.attr("height", height + margin.top + margin.bottom)
	.append("g")
	.attr("transform", "translate(" + margin.left + "," + margin.top + ")");

	var line = svg.append("g")
	.attr("class", "line")
	.selectAll("line")
	.data(e)
	.enter().append("line")
	.attr("transform", transform)
	.attr("y2", function(d) {
	return -height*d.vis;
	});

	var text = svg.append("g")
	.attr("class", "label")
	.selectAll("text")
	.data([3,5,15])
	.enter().append("text")
	.attr("x", function(d) { return "" + x(n) + ""; })
	.attr("y", function(d) { return -height(0.4+(+(d%3==0)) + 2(+(d%5==0))); })
	.style("fill", function(d) {
	return "rgb(" + 255(+(d%3==0))(+(d%5==0)) + ","
	+ 255(+(d%3==0))(1-+(d%5==0)) + ","
	+ 255(1-+(d%3==0))(+(d%5==0)) + ")";
	})
	.text(function(d) { return "x%" + d + "==0"; })
	.attr("font-family", "sans-serif")
	.attr("font-size", "20px");

	var xtext = svg.append("g")
	.selectAll("text")
	.data([""])
	.enter().append("text")
	.attr("x", width/2+32)
	.attr("y", height/2+20)
	.text("x = 0")
	.attr("font-family", "sans-serif")
	.attr("font-size", "20px");

	var sumtext = svg.append("g")
	.selectAll("text")
	.data([""])
	.enter().append("text")
	.attr("x", width/2)
	.attr("y", height/2+40)
	.text("Sum = 0")
	.attr("font-family", "sans-serif")
	.attr("font-size", "20px");

	var transition = d3.transition()
	.duration(100)
	.each("start", function start() {
	var i = test.shift();
	if (i.num<n+1) {
	e[i.num-1].on = 1;
	}
	if (i.num%3==0) {
	e[i.num-1].is3 = 1;
	}
	if (i.num%5==0) {
	e[i.num-1].is5 = 1;
	}
	if (i.num%5==0 \|\| i.num%3==0) {
	sum+=i.num;
	}
	if (i.num-1>0) {
	e[i.num-2].on = 0;
	e[i.num-2].acti = e[i.num-2].is3 + e[i.num-2].is5;
	}
	transition.each(function() {
	line.transition()
	.attr("transform", transform)
	.style("stroke", function(d) {
	if (d.acti) {
	return "rgb(" + 255(1-d.on)(d.is3)*(d.is5) + ","
	+ 255(1-d.on)(d.is3)*(1-d.is5) + ","
	+ 255(1-d.on)(1-d.is3)*(d.is5) + ")";
	}
	else if (!d.acti) {
	return "rgb(221,221,221)";
	}
	});
	xtext.transition()
	.text(function(d) {
	if (i.num<=n) {
	console.log(d);
	return "x = " + i.num;
	}
	});
	sumtext.transition()
	.text(function(d) {
	console.log(d);
	return "Sum = " + sum;
	});
	});
	if (test.length) {
	transition = transition.transition().each("start", start);
	}
	});

	function transform(d, i) {
	return "translate(" + x(i) + "," + height(-d.is3-d.is52)*d.vis + ")";
	}

	</script>
	</body>