Fix two sorting bugs in chord layout.

We still weren't sorting subgroups correctly. Also, we now sort chords by their
average value, rather than the source value, which works well with one-sided
chords (where either the source or target value is zero).

d3.js

@@ -10,7 +10,7 @@ try {
     d3_style_setProperty.call(this, name, value + "", priority);
   };
 }
-d3 = {version: "2.4.5"}; // semver
+d3 = {version: "2.4.6"}; // semver
 var d3_array = d3_arraySlice; // conversion for NodeLists
 
 function d3_arrayCopy(pseudoarray) {

d3.layout.js

@@ -116,7 +116,7 @@ d3.layout.chord = function() {
     x = 0, i = -1; while (++i < n) {
       x0 = x, j = -1; while (++j < n) {
         var di = groupIndex[i],
-            dj = subgroupIndex[i][j],
+            dj = subgroupIndex[di][j],
             v = matrix[di][dj];
         subgroups[di + "-" + dj] = {
           index: di,
@@ -153,7 +153,9 @@ d3.layout.chord = function() {
 
   function resort() {
     chords.sort(function(a, b) {
-      return sortChords(a.target.value, b.target.value);
+      return sortChords(
+          (a.source.value + a.target.value) / 2,
+          (b.source.value + b.target.value) / 2);
     });
   }
 

package.json

 {
   "name": "d3",
-  "version": "2.4.5",
+  "version": "2.4.6",
   "description": "A small, free JavaScript library for manipulating documents based on data.",
   "keywords": [
     "dom",

src/core/core.js

-d3 = {version: "2.4.5"}; // semver
+d3 = {version: "2.4.6"}; // semver

src/layout/chord.js

@@ -58,7 +58,7 @@ d3.layout.chord = function() {
     x = 0, i = -1; while (++i < n) {
       x0 = x, j = -1; while (++j < n) {
         var di = groupIndex[i],
-            dj = subgroupIndex[i][j],
+            dj = subgroupIndex[di][j],
             v = matrix[di][dj];
         subgroups[di + "-" + dj] = {
           index: di,
@@ -95,7 +95,9 @@ d3.layout.chord = function() {
 
   function resort() {
     chords.sort(function(a, b) {
-      return sortChords(a.target.value, b.target.value);
+      return sortChords(
+          (a.source.value + a.target.value) / 2,
+          (b.source.value + b.target.value) / 2);
     });
   }