in TestApplications/Web/js/lib/components/d3-3.4.13/src/layout/chord.js [16:101]
function relayout() {
var subgroups = {},
groupSums = [],
groupIndex = d3.range(n),
subgroupIndex = [],
k,
x,
x0,
i,
j;
chords = [];
groups = [];
// Compute the sum.
k = 0, i = -1; while (++i < n) {
x = 0, j = -1; while (++j < n) {
x += matrix[i][j];
}
groupSums.push(x);
subgroupIndex.push(d3.range(n));
k += x;
}
// Sort groups…
if (sortGroups) {
groupIndex.sort(function(a, b) {
return sortGroups(groupSums[a], groupSums[b]);
});
}
// Sort subgroups…
if (sortSubgroups) {
subgroupIndex.forEach(function(d, i) {
d.sort(function(a, b) {
return sortSubgroups(matrix[i][a], matrix[i][b]);
});
});
}
// Convert the sum to scaling factor for [0, 2pi].
// TODO Allow start and end angle to be specified.
// TODO Allow padding to be specified as percentage?
k = (τ - padding * n) / k;
// Compute the start and end angle for each group and subgroup.
// Note: Opera has a bug reordering object literal properties!
x = 0, i = -1; while (++i < n) {
x0 = x, j = -1; while (++j < n) {
var di = groupIndex[i],
dj = subgroupIndex[di][j],
v = matrix[di][dj],
a0 = x,
a1 = x += v * k;
subgroups[di + "-" + dj] = {
index: di,
subindex: dj,
startAngle: a0,
endAngle: a1,
value: v
};
}
groups[di] = {
index: di,
startAngle: x0,
endAngle: x,
value: (x - x0) / k
};
x += padding;
}
// Generate chords for each (non-empty) subgroup-subgroup link.
i = -1; while (++i < n) {
j = i - 1; while (++j < n) {
var source = subgroups[i + "-" + j],
target = subgroups[j + "-" + i];
if (source.value || target.value) {
chords.push(source.value < target.value
? {source: target, target: source}
: {source: source, target: target});
}
}
}
if (sortChords) resort();
}