Moved the unsuccessful indexing code out of testbed and renamed it

indexing_attempts/complicated_vectors.js

@@ -0,0 +1,261 @@
+// bad stuff
+
+function find_chords(chords, n) {
+	return chords.filter((c) => c[0].id === n.id || c[1].id === n.id);
+}
+
+function find_neighbours(chords, n) {
+	const c = find_chords(chords, n);
+	return c.map((c) => c[0].id === n.id ? c[1] : c[0])
+}
+
+
+
+// for a list of pairs [n1, n2] (these are nodes which share a common angle
+// from a center), find all the groups of nodes which don't appear in a pair
+// together
+
+function partition_nodes(pairs) {
+	let groups = [];
+	const seen = new Set();
+	for( const pair of pairs ) {
+		// both nodes are in a group already
+		if( seen.has(pair[0]) && seen.has(pair[1]) ) {
+			continue;
+		}
+		let already = false;
+		// check if either node is already in a group
+		for( const group of groups ) {
+			if( group.has(pair[0]) ) {
+				group.add(pair[1]);
+				seen.add(pair[1]);
+				already = true;
+				continue;
+			} else if( group.has(pair[1]) ) {
+				group.has(pair[0]);
+				seen.has(pair[0]);
+				already = true;
+				continue;
+			}
+		}
+		// if neither of the pair was in a former group, start a new group
+		if( !already ) {
+			groups.push(new Set(pair));
+		}
+		// collapse any groups which now have common elements
+		groups = collapse_groups(groups);
+	}
+	return groups;
+}
+
+// given a list of groups, if any have common elements, collapse them
+
+function collapse_groups(groups) {
+	const new_groups = [ ];
+	for( group of groups ) {
+		let collapsed = false;
+		for( new_group of new_groups ) {
+			const i = intersection(group, new_group);
+			if( i.size > 0 ) {
+				for( const e of group ) {
+					new_group.add(e);
+				}
+				collapsed = true;
+				break;
+			}
+		}
+		if( !collapsed ) {
+			new_groups.push(new Set(group));
+		}
+	}
+	return new_groups;
+}
+
+
+function intersection(s1, s2) {
+	const i = new Set();
+	for( const e of s1 ) {
+		if( s2.has(e) ) {
+			i.add(e)
+		}
+	}
+	return i;
+}
+
+function union(s1, s2) {
+	const u = new Set(s1);
+	for( const e of s2 ) {
+		u.add(e);
+	}
+	return u;
+}
+
+
+function vector_angle(n1, n2, n3) {
+	const v1 = new THREE.Vector4(n1.x, n1.y, n1.z, n1.w);
+	const v2 = new THREE.Vector4(n2.x, n2.y, n2.z, n2.w);
+	const v3 = new THREE.Vector4(n3.x, n3.y, n3.z, n3.w);
+	v2.sub(v1);
+	v3.sub(v1);
+	const dp = v2.dot(v3);
+	return Math.acos(dp / ( v2.length() * v3.length()));
+}
+
+function neighbour_angles_orig(chords, n) {
+	const ns = find_neighbours(chords, n);
+	const angles = {};
+	for( let i = 0; i < ns.length - 1; i++ ) {
+		for( let j = i + 1; j < ns.length; j++ ) {
+			const n2 = ns[i];
+			const n3 = ns[j];
+			const a = THREE.MathUtils.radToDeg(vector_angle(n, n2, n3));
+			const af = (a).toFixed(3);
+			if( ! (af in angles) ) {
+				angles[af] = [];
+			}
+			angles[af].push([n2.id, n3.id]);
+		}
+	}
+	return angles;
+}
+
+function neighbour_angles(chords, n, angle) {
+	const ns = find_neighbours(chords, n);
+	const pairs = [];
+	for( let i = 0; i < ns.length - 1; i++ ) {
+		for( let j = i + 1; j < ns.length; j++ ) {
+			const n2 = ns[i];
+			const n3 = ns[j];
+			const a = THREE.MathUtils.radToDeg(vector_angle(n, n2, n3));
+			const af = (a).toFixed(3);
+			if( af === angle ) {
+				pairs.push([n2.id, n3.id]);
+			}
+		}
+	}
+	return pairs;
+}
+
+
+function make_120_partition(nodes, n) {
+	const chords = find_all_chords(nodes);
+	const chord3 = chords["1.74806"];  // these are edges of the 600-cells;
+	const pairs60 = neighbour_angles(chord3, n, "60.000");
+	const icosas = partition_nodes(pairs60);
+
+	n.label = 1;
+	const angles = icosa_nodes(nodes, icosas[0]);
+	label_120_partition_r(nodes, chord3, 1, n, angles);
+}
+
+// recursive function to label a single 600-cell vertex partition of the 
+// 120-cell by following icosahedral nets
+// this doesn't work! completely - labels only 108-112
+
+function label_120_partition_r(nodes, chords, label, origin, neighbours) {
+	console.log(`label_120_partition_r ${origin.id}`);
+	console.log(neighbours.map((n) => n.id).join(', '));
+
+	// first try to label everything
+	const unlabelled = [];
+	for( const n of neighbours ) {
+		if( n.label === 0 ) {
+			console.log(`Labelled ${n.id} ${label}`);
+			n.label = label;
+			unlabelled.push(n);
+		} else if( n.label !== label ) {
+			console.log(`node ${n.id} is already in group ${n.label}`);
+			//return false;
+		}
+	}
+	for( const n of unlabelled ) { 
+		// the angles represent two icosahedral pyramids - partition them and
+		// pick the one which is at 60 to the edge we arrived on
+		//console.log(`looking for more neighbors for ${n}`);
+		const pairs60 = neighbour_angles(chords, n, "60.000");
+		const icosas = partition_nodes(pairs60);
+		const icosa = choose_icosa(nodes, origin, n, icosas);
+		const icosa_n = icosa_nodes(nodes, icosa);
+		console.log(`recursing to ${nice_icosa(nodes,icosa)}`);
+		return label_120_partition_r(nodes, chords, label, n, icosa_n);
+	}
+}
+
+// given a pair of icosa-sets, pick the one which is at the right angle to
+// the incoming vector
+
+function choose_icosa(nodes, origin, n1, icosas) {
+	for( const icosa of icosas ) {
+		const inodes = icosa_nodes(nodes, icosa);
+		const a60 = inodes.map((ni) => {
+			const a = THREE.MathUtils.radToDeg(vector_angle(n1, origin, ni));
+			return a.toFixed(3);
+		});
+		if( a60.filter((a) => a === "60.000").length > 0 ) {
+			return icosa;
+		}
+	}
+	console.log("No icosa found!");
+	return undefined;
+}
+
+function icosa_nodes(nodes, icosa) {
+	return Array.from(icosa).map((nid) => node_by_id(nodes, nid)).sort((a, b) => a.id - b.id);
+}
+
+function node_by_id(nodes, nid) {
+	const ns = nodes.filter((n) => n.id === nid);
+	return ns[0];
+}
+
+
+function enumerate_icosas(nodes) {
+	const chords = find_all_chords(nodes);
+	const chord3 = chords["1.74806"];  // these are edges of the 600-cells;
+
+	for( const n of nodes ) {
+		const pairs60 = neighbour_angles(chord3, n, "60.000");
+		const icosas = partition_nodes(pairs60);
+		for( const icosa of icosas ) {
+			const inodes = icosa_nodes(nodes, icosa);
+			console.log(icosa_to_csv(n.id, inodes).join(','));
+		}
+	}
+}
+
+
+function icosa_to_csv(nid, icosa) {
+	const cols = [ nid ];
+	const ia = icosa.map((n) => n.id);
+	for( let i = 1; i < 601; i++ ) {
+		if( ia.includes(i) ) {
+			cols.push(i);
+		} else {
+			cols.push('')
+		}
+	}
+	return cols;
+}
+
+
+function start_icosas(nodes, chords, origin) {
+	const pairs60 = neighbour_angles(chords, origin, "60.000");
+	return partition_nodes(pairs60).map((i) => nice_icosa(nodes, i));
+}
+
+
+
+function next_icosa(nodes, chords, origin, nid) {
+	const n = node_by_id(nodes, nid);
+	const pairs60 = neighbour_angles(chords, n, "60.000");
+	const icosas = partition_nodes(pairs60);
+	const icosa = choose_icosa(nodes, origin, n, icosas);
+
+	return nice_icosa(nodes, icosa);
+}
+
+function nice_icosa(nodes, icosa) {
+	return icosa_nodes(nodes, icosa).map((n) => n.id).join(', ');
+}
+
+

indexing_attempts/graph_traversal.js

@@ -0,0 +1,78 @@
+// New approach with tetrahedral coloring
+
+function find_edges(links, nid) {
+	return links.filter((l) => l.source === nid || l.target === nid );
+}
+
+
+function find_adjacent(links, nid) {
+	return find_edges(links, nid).map((l) => {
+		if( l.source === nid ) {
+			return l.target;
+		} else {
+			return l.source;
+		}
+	});
+}
+
+function iterate_graph(nodes, links, n, fn) {
+	const queue = [];
+	const seen = {};
+	const nodes_id = {};
+	nodes.map((n) => nodes_id[n.id] = n);
+
+	queue.push(n.id);
+	seen[n.id] = true;
+	fn(n);
+
+	while( queue.length > 0 ) {
+		const v = queue.shift();
+		find_adjacent(links, v).map((aid) => {
+			if( !(aid in seen) ) {
+				seen[aid] = true;
+				queue.push(aid);
+				fn(nodes_id[aid]);
+			}
+		})
+	}
+}
+
+
+
+
+// stupid tetrahedral labelling
+// keeps getting stuck
+
+
+function naive_label_120cell(nodes, links, n) {
+	const nodes_id = {};
+	nodes.map((n) => nodes_id[n.id] = n);
+	iterate_graph(nodes, links, nodes[0], (n) => {
+		const cols = new Set();
+		const nbors = find_adjacent(links, n.id);
+		for( const nb of nbors ) {
+			if( nodes_id[nb].label > 0 ) {
+				cols.add(nodes_id[nb].label);
+			}
+			for( const nb2 of find_adjacent(links, nb) ) {
+				if( nb2 !== n.id && nodes_id[nb].label > 0 ) {
+					cols.add(nodes_id[nb2].label);
+				}
+			}
+		}
+		const pcols = [ 1, 2, 3, 4, 5 ].filter((c) => !cols.has(c));
+		if( pcols.length < 1 ) {
+			console.log(`Got stuck, no options at ${n.id}`);
+			return false;
+		} else {
+			n.label = pcols[0];
+			console.log(`found ${pcols.length} colors for node ${n.id}`);
+			console.log(`applied ${pcols[0]} to node ${n.id}`);
+			return true;
+		}
+	});
+}
+
+
+
+