(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.graphlib = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
/**
 * Copyright (c) 2014, Chris Pettitt
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

var lib = require("./lib");

module.exports = {
  Graph: lib.Graph,
  json: require("./lib/json"),
  alg: require("./lib/alg"),
  version: lib.version
};

},{"./lib":17,"./lib/alg":8,"./lib/json":18}],2:[function(require,module,exports){
var _ = require("../lodash");

module.exports = components;

function components(g) {
  var visited = {},
      cmpts = [],
      cmpt;

  function dfs(v) {
    if (_.has(visited, v)) return;
    visited[v] = true;
    cmpt.push(v);
    _.each(g.successors(v), dfs);
    _.each(g.predecessors(v), dfs);
  }

  _.each(g.nodes(), function(v) {
    cmpt = [];
    dfs(v);
    if (cmpt.length) {
      cmpts.push(cmpt);
    }
  });

  return cmpts;
}

},{"../lodash":19}],3:[function(require,module,exports){
var _ = require("../lodash");

module.exports = dfs;

/*
 * A helper that preforms a pre- or post-order traversal on the input graph
 * and returns the nodes in the order they were visited. If the graph is
 * undirected then this algorithm will navigate using neighbors. If the graph
 * is directed then this algorithm will navigate using successors.
 *
 * Order must be one of "pre" or "post".
 */
function dfs(g, vs, order) {
  if (!_.isArray(vs)) {
    vs = [vs];
  }

  var navigation = (g.isDirected() ? g.successors : g.neighbors).bind(g);

  var acc = [],
      visited = {};
  _.each(vs, function(v) {
    if (!g.hasNode(v)) {
      throw new Error("Graph does not have node: " + v);
    }

    doDfs(g, v, order === "post", visited, navigation, acc);
  });
  return acc;
}

function doDfs(g, v, postorder, visited, navigation, acc) {
  if (!_.has(visited, v)) {
    visited[v] = true;

    if (!postorder) { acc.push(v); }
    _.each(navigation(v), function(w) {
      doDfs(g, w, postorder, visited, navigation, acc);
    });
    if (postorder) { acc.push(v); }
  }
}

},{"../lodash":19}],4:[function(require,module,exports){
var dijkstra = require("./dijkstra"),
    _ = require("../lodash");

module.exports = dijkstraAll;

function dijkstraAll(g, weightFunc, edgeFunc) {
  return _.transform(g.nodes(), function(acc, v) {
    acc[v] = dijkstra(g, v, weightFunc, edgeFunc);
  }, {});
}

},{"../lodash":19,"./dijkstra":5}],5:[function(require,module,exports){
var _ = require("../lodash"),
    PriorityQueue = require("../data/priority-queue");

module.exports = dijkstra;

var DEFAULT_WEIGHT_FUNC = _.constant(1);

function dijkstra(g, source, weightFn, edgeFn) {
  return runDijkstra(g, String(source),
                     weightFn || DEFAULT_WEIGHT_FUNC,
                     edgeFn || function(v) { return g.outEdges(v); });
}

function runDijkstra(g, source, weightFn, edgeFn) {
  var results = {},
      pq = new PriorityQueue(),
      v, vEntry;

  var updateNeighbors = function(edge) {
    var w = edge.v !== v ? edge.v : edge.w,
        wEntry = results[w],
        weight = weightFn(edge),
        distance = vEntry.distance + weight;

    if (weight < 0) {
      throw new Error("dijkstra does not allow negative edge weights. " +
                      "Bad edge: " + edge + " Weight: " + weight);
    }

    if (distance < wEntry.distance) {
      wEntry.distance = distance;
      wEntry.predecessor = v;
      pq.decrease(w, distance);
    }
  };

  g.nodes().forEach(function(v) {
    var distance = v === source ? 0 : Number.POSITIVE_INFINITY;
    results[v] = { distance: distance };
    pq.add(v, distance);
  });

  while (pq.size() > 0) {
    v = pq.removeMin();
    vEntry = results[v];
    if (vEntry.distance === Number.POSITIVE_INFINITY) {
      break;
    }

    edgeFn(v).forEach(updateNeighbors);
  }

  return results;
}

},{"../data/priority-queue":15,"../lodash":19}],6:[function(require,module,exports){
var _ = require("../lodash"),
    tarjan = require("./tarjan");

module.exports = findCycles;

function findCycles(g) {
  return _.filter(tarjan(g), function(cmpt) {
    return cmpt.length > 1 || (cmpt.length === 1 && g.hasEdge(cmpt[0], cmpt[0]));
  });
}

},{"../lodash":19,"./tarjan":13}],7:[function(require,module,exports){
var _ = require("../lodash");

module.exports = floydWarshall;

var DEFAULT_WEIGHT_FUNC = _.constant(1);

function floydWarshall(g, weightFn, edgeFn) {
  return runFloydWarshall(g,
                          weightFn || DEFAULT_WEIGHT_FUNC,
                          edgeFn || function(v) { return g.outEdges(v); });
}

function runFloydWarshall(g, weightFn, edgeFn) {
  var results = {},
      nodes = g.nodes();

  nodes.forEach(function(v) {
    results[v] = {};
    results[v][v] = { distance: 0 };
    nodes.forEach(function(w) {
      if (v !== w) {
        results[v][w] = { distance: Number.POSITIVE_INFINITY };
      }
    });
    edgeFn(v).forEach(function(edge) {
      var w = edge.v === v ? edge.w : edge.v,
          d = weightFn(edge);
      results[v][w] = { distance: d, predecessor: v };
    });
  });

  nodes.forEach(function(k) {
    var rowK = results[k];
    nodes.forEach(function(i) {
      var rowI = results[i];
      nodes.forEach(function(j) {
        var ik = rowI[k];
        var kj = rowK[j];
        var ij = rowI[j];
        var altDistance = ik.distance + kj.distance;
        if (altDistance < ij.distance) {
          ij.distance = altDistance;
          ij.predecessor = kj.predecessor;
        }
      });
    });
  });

  return results;
}

},{"../lodash":19}],8:[function(require,module,exports){
module.exports = {
  components: require("./components"),
  dijkstra: require("./dijkstra"),
  dijkstraAll: require("./dijkstra-all"),
  findCycles: require("./find-cycles"),
  floydWarshall: require("./floyd-warshall"),
  isAcyclic: require("./is-acyclic"),
  postorder: require("./postorder"),
  preorder: require("./preorder"),
  prim: require("./prim"),
  tarjan: require("./tarjan"),
  topsort: require("./topsort")
};

},{"./components":2,"./dijkstra":5,"./dijkstra-all":4,"./find-cycles":6,"./floyd-warshall":7,"./is-acyclic":9,"./postorder":10,"./preorder":11,"./prim":12,"./tarjan":13,"./topsort":14}],9:[function(require,module,exports){
var topsort = require("./topsort");

module.exports = isAcyclic;

function isAcyclic(g) {
  try {
    topsort(g);
  } catch (e) {
    if (e instanceof topsort.CycleException) {
      return false;
    }
    throw e;
  }
  return true;
}

},{"./topsort":14}],10:[function(require,module,exports){
var dfs = require("./dfs");

module.exports = postorder;

function postorder(g, vs) {
  return dfs(g, vs, "post");
}

},{"./dfs":3}],11:[function(require,module,exports){
var dfs = require("./dfs");

module.exports = preorder;

function preorder(g, vs) {
  return dfs(g, vs, "pre");
}

},{"./dfs":3}],12:[function(require,module,exports){
var _ = require("../lodash"),
    Graph = require("../graph"),
    PriorityQueue = require("../data/priority-queue");

module.exports = prim;

function prim(g, weightFunc) {
  var result = new Graph(),
      parents = {},
      pq = new PriorityQueue(),
      v;

  function updateNeighbors(edge) {
    var w = edge.v === v ? edge.w : edge.v,
        pri = pq.priority(w);
    if (pri !== undefined) {
      var edgeWeight = weightFunc(edge);
      if (edgeWeight < pri) {
        parents[w] = v;
        pq.decrease(w, edgeWeight);
      }
    }
  }

  if (g.nodeCount() === 0) {
    return result;
  }

  _.each(g.nodes(), function(v) {
    pq.add(v, Number.POSITIVE_INFINITY);
    result.setNode(v);
  });

  // Start from an arbitrary node
  pq.decrease(g.nodes()[0], 0);

  var init = false;
  while (pq.size() > 0) {
    v = pq.removeMin();
    if (_.has(parents, v)) {
      result.setEdge(v, parents[v]);
    } else if (init) {
      throw new Error("Input graph is not connected: " + g);
    } else {
      init = true;
    }

    g.nodeEdges(v).forEach(updateNeighbors);
  }

  return result;
}

},{"../data/priority-queue":15,"../graph":16,"../lodash":19}],13:[function(require,module,exports){
var _ = require("../lodash");

module.exports = tarjan;

function tarjan(g) {
  var index = 0,
      stack = [],
      visited = {}, // node id -> { onStack, lowlink, index }
      results = [];

  function dfs(v) {
    var entry = visited[v] = {
      onStack: true,
      lowlink: index,
      index: index++
    };
    stack.push(v);

    g.successors(v).forEach(function(w) {
      if (!_.has(visited, w)) {
        dfs(w);
        entry.lowlink = Math.min(entry.lowlink, visited[w].lowlink);
      } else if (visited[w].onStack) {
        entry.lowlink = Math.min(entry.lowlink, visited[w].index);
      }
    });

    if (entry.lowlink === entry.index) {
      var cmpt = [],
          w;
      do {
        w = stack.pop();
        visited[w].onStack = false;
        cmpt.push(w);
      } while (v !== w);
      results.push(cmpt);
    }
  }

  g.nodes().forEach(function(v) {
    if (!_.has(visited, v)) {
      dfs(v);
    }
  });

  return results;
}

},{"../lodash":19}],14:[function(require,module,exports){
var _ = require("../lodash");

module.exports = topsort;
topsort.CycleException = CycleException;

function topsort(g) {
  var visited = {},
      stack = {},
      results = [];

  function visit(node) {
    if (_.has(stack, node)) {
      throw new CycleException();
    }

    if (!_.has(visited, node)) {
      stack[node] = true;
      visited[node] = true;
      _.each(g.predecessors(node), visit);
      delete stack[node];
      results.push(node);
    }
  }

  _.each(g.sinks(), visit);

  if (_.size(visited) !== g.nodeCount()) {
    throw new CycleException();
  }

  return results;
}

function CycleException() {}

},{"../lodash":19}],15:[function(require,module,exports){
var _ = require("../lodash");

module.exports = PriorityQueue;

/**
 * A min-priority queue data structure. This algorithm is derived from Cormen,
 * et al., "Introduction to Algorithms". The basic idea of a min-priority
 * queue is that you can efficiently (in O(1) time) get the smallest key in
 * the queue. Adding and removing elements takes O(log n) time. A key can
 * have its priority decreased in O(log n) time.
 */
function PriorityQueue() {
  this._arr = [];
  this._keyIndices = {};
}

/**
 * Returns the number of elements in the queue. Takes `O(1)` time.
 */
PriorityQueue.prototype.size = function() {
  return this._arr.length;
};

/**
 * Returns the keys that are in the queue. Takes `O(n)` time.
 */
PriorityQueue.prototype.keys = function() {
  return this._arr.map(function(x) { return x.key; });
};

/**
 * Returns `true` if **key** is in the queue and `false` if not.
 */
PriorityQueue.prototype.has = function(key) {
  return _.has(this._keyIndices, key);
};

/**
 * Returns the priority for **key**. If **key** is not present in the queue
 * then this function returns `undefined`. Takes `O(1)` time.
 *
 * @param {Object} key
 */
PriorityQueue.prototype.priority = function(key) {
  var index = this._keyIndices[key];
  if (index !== undefined) {
    return this._arr[index].priority;
  }
};

/**
 * Returns the key for the minimum element in this queue. If the queue is
 * empty this function throws an Error. Takes `O(1)` time.
 */
PriorityQueue.prototype.min = function() {
  if (this.size() === 0) {
    throw new Error("Queue underflow");
  }
  return this._arr[0].key;
};

/**
 * Inserts a new key into the priority queue. If the key already exists in
 * the queue this function returns `false`; otherwise it will return `true`.
 * Takes `O(n)` time.
 *
 * @param {Object} key the key to add
 * @param {Number} priority the initial priority for the key
 */
PriorityQueue.prototype.add = function(key, priority) {
  var keyIndices = this._keyIndices;
  key = String(key);
  if (!_.has(keyIndices, key)) {
    var arr = this._arr;
    var index = arr.length;
    keyIndices[key] = index;
    arr.push({key: key, priority: priority});
    this._decrease(index);
    return true;
  }
  return false;
};

/**
 * Removes and returns the smallest key in the queue. Takes `O(log n)` time.
 */
PriorityQueue.prototype.removeMin = function() {
  this._swap(0, this._arr.length - 1);
  var min = this._arr.pop();
  delete this._keyIndices[min.key];
  this._heapify(0);
  return min.key;
};

/**
 * Decreases the priority for **key** to **priority**. If the new priority is
 * greater than the previous priority, this function will throw an Error.
 *
 * @param {Object} key the key for which to raise priority
 * @param {Number} priority the new priority for the key
 */
PriorityQueue.prototype.decrease = function(key, priority) {
  var index = this._keyIndices[key];
  if (priority > this._arr[index].priority) {
    throw new Error("New priority is greater than current priority. " +
        "Key: " + key + " Old: " + this._arr[index].priority + " New: " + priority);
  }
  this._arr[index].priority = priority;
  this._decrease(index);
};

PriorityQueue.prototype._heapify = function(i) {
  var arr = this._arr;
  var l = 2 * i,
      r = l + 1,
      largest = i;
  if (l < arr.length) {
    largest = arr[l].priority < arr[largest].priority ? l : largest;
    if (r < arr.length) {
      largest = arr[r].priority < arr[largest].priority ? r : largest;
    }
    if (largest !== i) {
      this._swap(i, largest);
      this._heapify(largest);
    }
  }
};

PriorityQueue.prototype._decrease = function(index) {
  var arr = this._arr;
  var priority = arr[index].priority;
  var parent;
  while (index !== 0) {
    parent = index >> 1;
    if (arr[parent].priority < priority) {
      break;
    }
    this._swap(index, parent);
    index = parent;
  }
};

PriorityQueue.prototype._swap = function(i, j) {
  var arr = this._arr;
  var keyIndices = this._keyIndices;
  var origArrI = arr[i];
  var origArrJ = arr[j];
  arr[i] = origArrJ;
  arr[j] = origArrI;
  keyIndices[origArrJ.key] = i;
  keyIndices[origArrI.key] = j;
};

},{"../lodash":19}],16:[function(require,module,exports){
"use strict";

var _ = require("./lodash");

module.exports = Graph;

var DEFAULT_EDGE_NAME = "\x00",
    GRAPH_NODE = "\x00",
    EDGE_KEY_DELIM = "\x01";

// Implementation notes:
//
//  * Node id query functions should return string ids for the nodes
//  * Edge id query functions should return an "edgeObj", edge object, that is
//    composed of enough information to uniquely identify an edge: {v, w, name}.
//  * Internally we use an "edgeId", a stringified form of the edgeObj, to
//    reference edges. This is because we need a performant way to look these
//    edges up and, object properties, which have string keys, are the closest
//    we're going to get to a performant hashtable in JavaScript.

function Graph(opts) {
  this._isDirected = _.has(opts, "directed") ? opts.directed : true;
  this._isMultigraph = _.has(opts, "multigraph") ? opts.multigraph : false;
  this._isCompound = _.has(opts, "compound") ? opts.compound : false;

  // Label for the graph itself
  this._label = undefined;

  // Defaults to be set when creating a new node
  this._defaultNodeLabelFn = _.constant(undefined);

  // Defaults to be set when creating a new edge
  this._defaultEdgeLabelFn = _.constant(undefined);

  // v -> label
  this._nodes = {};

  if (this._isCompound) {
    // v -> parent
    this._parent = {};

    // v -> children
    this._children = {};
    this._children[GRAPH_NODE] = {};
  }

  // v -> edgeObj
  this._in = {};

  // u -> v -> Number
  this._preds = {};

  // v -> edgeObj
  this._out = {};

  // v -> w -> Number
  this._sucs = {};

  // e -> edgeObj
  this._edgeObjs = {};

  // e -> label
  this._edgeLabels = {};
}

/* Number of nodes in the graph. Should only be changed by the implementation. */
Graph.prototype._nodeCount = 0;

/* Number of edges in the graph. Should only be changed by the implementation. */
Graph.prototype._edgeCount = 0;


/* === Graph functions ========= */

Graph.prototype.isDirected = function() {
  return this._isDirected;
};

Graph.prototype.isMultigraph = function() {
  return this._isMultigraph;
};

Graph.prototype.isCompound = function() {
  return this._isCompound;
};

Graph.prototype.setGraph = function(label) {
  this._label = label;
  return this;
};

Graph.prototype.graph = function() {
  return this._label;
};


/* === Node functions ========== */

Graph.prototype.setDefaultNodeLabel = function(newDefault) {
  if (!_.isFunction(newDefault)) {
    newDefault = _.constant(newDefault);
  }
  this._defaultNodeLabelFn = newDefault;
  return this;
};

Graph.prototype.nodeCount = function() {
  return this._nodeCount;
};

Graph.prototype.nodes = function() {
  return _.keys(this._nodes);
};

Graph.prototype.sources = function() {
  return _.filter(this.nodes(), _.bind(function(v) {
    return _.isEmpty(this._in[v]);
  }, this));
};

Graph.prototype.sinks = function() {
  return _.filter(this.nodes(), _.bind(function(v) {
    return _.isEmpty(this._out[v]);
  }, this));
};

Graph.prototype.setNodes = function(vs, value) {
  var args = arguments;
  _.each(vs, _.bind(function(v) {
    if (args.length > 1) {
      this.setNode(v, value);
    } else {
      this.setNode(v);
    }
  }, this));
  return this;
};

Graph.prototype.setNode = function(v, value) {
  if (_.has(this._nodes, v)) {
    if (arguments.length > 1) {
      this._nodes[v] = value;
    }
    return this;
  }

  this._nodes[v] = arguments.length > 1 ? value : this._defaultNodeLabelFn(v);
  if (this._isCompound) {
    this._parent[v] = GRAPH_NODE;
    this._children[v] = {};
    this._children[GRAPH_NODE][v] = true;
  }
  this._in[v] = {};
  this._preds[v] = {};
  this._out[v] = {};
  this._sucs[v] = {};
  ++this._nodeCount;
  return this;
};

Graph.prototype.node = function(v) {
  return this._nodes[v];
};

Graph.prototype.hasNode = function(v) {
  return _.has(this._nodes, v);
};

Graph.prototype.removeNode =  function(v) {
  var self = this;
  if (_.has(this._nodes, v)) {
    var removeEdge = function(e) { self.removeEdge(self._edgeObjs[e]); };
    delete this._nodes[v];
    if (this._isCompound) {
      this._removeFromParentsChildList(v);
      delete this._parent[v];
      _.each(this.children(v), _.bind(function(child) {
        this.setParent(child);
      }, this));
      delete this._children[v];
    }
    _.each(_.keys(this._in[v]), removeEdge);
    delete this._in[v];
    delete this._preds[v];
    _.each(_.keys(this._out[v]), removeEdge);
    delete this._out[v];
    delete this._sucs[v];
    --this._nodeCount;
  }
  return this;
};

Graph.prototype.setParent = function(v, parent) {
  if (!this._isCompound) {
    throw new Error("Cannot set parent in a non-compound graph");
  }

  if (_.isUndefined(parent)) {
    parent = GRAPH_NODE;
  } else {
    // Coerce parent to string
    parent += "";
    for (var ancestor = parent;
         !_.isUndefined(ancestor);
         ancestor = this.parent(ancestor)) {
      if (ancestor === v) {
        throw new Error("Setting " + parent+ " as parent of " + v +
                        " would create create a cycle");
      }
    }

    this.setNode(parent);
  }

  this.setNode(v);
  this._removeFromParentsChildList(v);
  this._parent[v] = parent;
  this._children[parent][v] = true;
  return this;
};

Graph.prototype._removeFromParentsChildList = function(v) {
  delete this._children[this._parent[v]][v];
};

Graph.prototype.parent = function(v) {
  if (this._isCompound) {
    var parent = this._parent[v];
    if (parent !== GRAPH_NODE) {
      return parent;
    }
  }
};

Graph.prototype.children = function(v) {
  if (_.isUndefined(v)) {
    v = GRAPH_NODE;
  }

  if (this._isCompound) {
    var children = this._children[v];
    if (children) {
      return _.keys(children);
    }
  } else if (v === GRAPH_NODE) {
    return this.nodes();
  } else if (this.hasNode(v)) {
    return [];
  }
};

Graph.prototype.predecessors = function(v) {
  var predsV = this._preds[v];
  if (predsV) {
    return _.keys(predsV);
  }
};

Graph.prototype.successors = function(v) {
  var sucsV = this._sucs[v];
  if (sucsV) {
    return _.keys(sucsV);
  }
};

Graph.prototype.neighbors = function(v) {
  var preds = this.predecessors(v);
  if (preds) {
    return _.union(preds, this.successors(v));
  }
};

Graph.prototype.filterNodes = function(filter) {
  var copy = new this.constructor({
    directed: this._isDirected,
    multigraph: this._isMultigraph,
    compound: this._isCompound
  });

  copy.setGraph(this.graph());

  _.each(this._nodes, _.bind(function(value, v) {
    if (filter(v)) {
      copy.setNode(v, value);
    }
  }, this));

  _.each(this._edgeObjs, _.bind(function(e) {
    if (copy.hasNode(e.v) && copy.hasNode(e.w)) {
      copy.setEdge(e, this.edge(e));
    }
  }, this));

  var self = this;
  var parents = {};
  function findParent(v) {
    var parent = self.parent(v);
    if (parent === undefined || copy.hasNode(parent)) {
      parents[v] = parent;
      return parent;
    } else if (parent in parents) {
      return parents[parent];
    } else {
      return findParent(parent);
    }
  }

  if (this._isCompound) {
    _.each(copy.nodes(), function(v) {
      copy.setParent(v, findParent(v));
    });
  }

  return copy;
};

/* === Edge functions ========== */

Graph.prototype.setDefaultEdgeLabel = function(newDefault) {
  if (!_.isFunction(newDefault)) {
    newDefault = _.constant(newDefault);
  }
  this._defaultEdgeLabelFn = newDefault;
  return this;
};

Graph.prototype.edgeCount = function() {
  return this._edgeCount;
};

Graph.prototype.edges = function() {
  return _.values(this._edgeObjs);
};

Graph.prototype.setPath = function(vs, value) {
  var self = this,
      args = arguments;
  _.reduce(vs, function(v, w) {
    if (args.length > 1) {
      self.setEdge(v, w, value);
    } else {
      self.setEdge(v, w);
    }
    return w;
  });
  return this;
};

/*
 * setEdge(v, w, [value, [name]])
 * setEdge({ v, w, [name] }, [value])
 */
Graph.prototype.setEdge = function() {
  var v, w, name, value,
      valueSpecified = false,
      arg0 = arguments[0];

  if (typeof arg0 === "object" && arg0 !== null && "v" in arg0) {
    v = arg0.v;
    w = arg0.w;
    name = arg0.name;
    if (arguments.length === 2) {
      value = arguments[1];
      valueSpecified = true;
    }
  } else {
    v = arg0;
    w = arguments[1];
    name = arguments[3];
    if (arguments.length > 2) {
      value = arguments[2];
      valueSpecified = true;
    }
  }

  v = "" + v;
  w = "" + w;
  if (!_.isUndefined(name)) {
    name = "" + name;
  }

  var e = edgeArgsToId(this._isDirected, v, w, name);
  if (_.has(this._edgeLabels, e)) {
    if (valueSpecified) {
      this._edgeLabels[e] = value;
    }
    return this;
  }

  if (!_.isUndefined(name) && !this._isMultigraph) {
    throw new Error("Cannot set a named edge when isMultigraph = false");
  }

  // It didn't exist, so we need to create it.
  // First ensure the nodes exist.
  this.setNode(v);
  this.setNode(w);

  this._edgeLabels[e] = valueSpecified ? value : this._defaultEdgeLabelFn(v, w, name);

  var edgeObj = edgeArgsToObj(this._isDirected, v, w, name);
  // Ensure we add undirected edges in a consistent way.
  v = edgeObj.v;
  w = edgeObj.w;

  Object.freeze(edgeObj);
  this._edgeObjs[e] = edgeObj;
  incrementOrInitEntry(this._preds[w], v);
  incrementOrInitEntry(this._sucs[v], w);
  this._in[w][e] = edgeObj;
  this._out[v][e] = edgeObj;
  this._edgeCount++;
  return this;
};

Graph.prototype.edge = function(v, w, name) {
  var e = (arguments.length === 1
            ? edgeObjToId(this._isDirected, arguments[0])
            : edgeArgsToId(this._isDirected, v, w, name));
  return this._edgeLabels[e];
};

Graph.prototype.hasEdge = function(v, w, name) {
  var e = (arguments.length === 1
            ? edgeObjToId(this._isDirected, arguments[0])
            : edgeArgsToId(this._isDirected, v, w, name));
  return _.has(this._edgeLabels, e);
};

Graph.prototype.removeEdge = function(v, w, name) {
  var e = (arguments.length === 1
            ? edgeObjToId(this._isDirected, arguments[0])
            : edgeArgsToId(this._isDirected, v, w, name)),
      edge = this._edgeObjs[e];
  if (edge) {
    v = edge.v;
    w = edge.w;
    delete this._edgeLabels[e];
    delete this._edgeObjs[e];
    decrementOrRemoveEntry(this._preds[w], v);
    decrementOrRemoveEntry(this._sucs[v], w);
    delete this._in[w][e];
    delete this._out[v][e];
    this._edgeCount--;
  }
  return this;
};

Graph.prototype.inEdges = function(v, u) {
  var inV = this._in[v];
  if (inV) {
    var edges = _.values(inV);
    if (!u) {
      return edges;
    }
    return _.filter(edges, function(edge) { return edge.v === u; });
  }
};

Graph.prototype.outEdges = function(v, w) {
  var outV = this._out[v];
  if (outV) {
    var edges = _.values(outV);
    if (!w) {
      return edges;
    }
    return _.filter(edges, function(edge) { return edge.w === w; });
  }
};

Graph.prototype.nodeEdges = function(v, w) {
  var inEdges = this.inEdges(v, w);
  if (inEdges) {
    return inEdges.concat(this.outEdges(v, w));
  }
};

function incrementOrInitEntry(map, k) {
  if (map[k]) {
    map[k]++;
  } else {
    map[k] = 1;
  }
}

function decrementOrRemoveEntry(map, k) {
  if (!--map[k]) { delete map[k]; }
}

function edgeArgsToId(isDirected, v_, w_, name) {
  var v = "" + v_;
  var w = "" + w_;
  if (!isDirected && v > w) {
    var tmp = v;
    v = w;
    w = tmp;
  }
  return v + EDGE_KEY_DELIM + w + EDGE_KEY_DELIM +
             (_.isUndefined(name) ? DEFAULT_EDGE_NAME : name);
}

function edgeArgsToObj(isDirected, v_, w_, name) {
  var v = "" + v_;
  var w = "" + w_;
  if (!isDirected && v > w) {
    var tmp = v;
    v = w;
    w = tmp;
  }
  var edgeObj =  { v: v, w: w };
  if (name) {
    edgeObj.name = name;
  }
  return edgeObj;
}

function edgeObjToId(isDirected, edgeObj) {
  return edgeArgsToId(isDirected, edgeObj.v, edgeObj.w, edgeObj.name);
}

},{"./lodash":19}],17:[function(require,module,exports){
// Includes only the "core" of graphlib
module.exports = {
  Graph: require("./graph"),
  version: require("./version")
};

},{"./graph":16,"./version":20}],18:[function(require,module,exports){
var _ = require("./lodash"),
    Graph = require("./graph");

module.exports = {
  write: write,
  read: read
};

function write(g) {
  var json = {
    options: {
      directed: g.isDirected(),
      multigraph: g.isMultigraph(),
      compound: g.isCompound()
    },
    nodes: writeNodes(g),
    edges: writeEdges(g)
  };
  if (!_.isUndefined(g.graph())) {
    json.value = _.clone(g.graph());
  }
  return json;
}

function writeNodes(g) {
  return _.map(g.nodes(), function(v) {
    var nodeValue = g.node(v),
        parent = g.parent(v),
        node = { v: v };
    if (!_.isUndefined(nodeValue)) {
      node.value = nodeValue;
    }
    if (!_.isUndefined(parent)) {
      node.parent = parent;
    }
    return node;
  });
}

function writeEdges(g) {
  return _.map(g.edges(), function(e) {
    var edgeValue = g.edge(e),
        edge = { v: e.v, w: e.w };
    if (!_.isUndefined(e.name)) {
      edge.name = e.name;
    }
    if (!_.isUndefined(edgeValue)) {
      edge.value = edgeValue;
    }
    return edge;
  });
}

function read(json) {
  var g = new Graph(json.options).setGraph(json.value);
  _.each(json.nodes, function(entry) {
    g.setNode(entry.v, entry.value);
    if (entry.parent) {
      g.setParent(entry.v, entry.parent);
    }
  });
  _.each(json.edges, function(entry) {
    g.setEdge({ v: entry.v, w: entry.w, name: entry.name }, entry.value);
  });
  return g;
}

},{"./graph":16,"./lodash":19}],19:[function(require,module,exports){
/* global window */

var lodash;

if (typeof require === "function") {
  try {
    lodash = require("lodash");
  } catch (e) {}
}

if (!lodash) {
  lodash = window._;
}

module.exports = lodash;

},{"lodash":undefined}],20:[function(require,module,exports){
module.exports = '2.1.1';

},{}]},{},[1])(1)
});