Graph OrientDB：如何在忽略某些边的情况下使用dijkstra函数查询图形
我试图从orientdb查询数据，但忽略了一些边 我的查询的形式如下：Graph OrientDB：如何在忽略某些边的情况下使用dijkstra函数查询图形,graph,orientdb,dijkstra,Graph,Orientdb,Dijkstra,我试图从orientdb查询数据，但忽略了一些边 我的查询的形式如下： select expand(dijkstra(#12:15,#12:20,'property','both')) 但正如前面提到的，我想忽略图的一些边 有什么建议吗 编辑 这是我的图形结构。 作为顶点的站 作为边的路径 非常感谢@Ivan Mainetti的回答，我已经试过了 这是我的主要任务 String nomeDb = "Demo2"; try { System.out.println(
select expand(dijkstra(#12:15,#12:20,'property','both'))
String nomeDb = "Demo2";
try {
System.out.println("Before connect OServerAdmin");
OServerAdmin serverAdmin = new OServerAdmin("remote:128.199.xxx.xxx/"+nomeDb).connect("admin","password");
System.out.println("After connect");
if(serverAdmin.existsDatabase()){ // il db esiste
System.out.println("in if");
//connessione a db
OrientGraph g = new OrientGraph("remote:128.199.xxx.xxx/"+nomeDb);
DijkstraExcl d = new DijkstraExcl(g, "Path", "distance");
Set<String> ex =new HashSet<String>();
//------------------------------------------------
Vertex start = g.getVertex("#12:6");
Vertex end = g.getVertex("#12:11");
ex.add("#13:0");
Direction direction = Direction.OUT;
System.out.println(d.getPath(start,end,direction,ex));
System.out.println(d.getPathString(start,end,direction,ex));
System.out.println(d.getWeight(start,end,direction,ex));
//------------------------------------------------
//chiude db
g.shutdown();
}
else{
System.out.println("Il database '"+ nomeDb + "' non esiste");
}
serverAdmin.close();
} catch (IOException e) {
e.printStackTrace();
}
[12:6,12:8,12:10,12:11]一种方法是使用OrientDB对无穷大的支持，如console.sh typescript所示：
> select 1.0E400
----+------+--------
# |@CLASS|1
----+------+--------
0 |null |Infinity
----+------+--------
> select eval('0 < 1.0E400')
----+------+----
# |@CLASS|eval
----+------+----
0 |null |true
----+------+----
> select -1.0E400
----+------+---------
# |@CLASS|-1
----+------+---------
0 |null |-Infinity
----+------+---------
> select eval('0 < -1.0E400')
----+------+-----
# |@CLASS|eval
----+------+-----
0 |null |false
----+------+-----
尝试使用以下JS函数，该函数的参数为ridFrom、ridTo、property、direction和excludedges。 使用Studio，您可以使用以下命令进行尝试：
select expand(result) from (select myFunction("12:6","12:11","distance","out","[#13:0]") as result)
var g=orient.getGraph();
var listEdges=excludeEdges.substring(1,excludeEdges.length-1).split(",");
var S=[], T=[] , id_weigth=[] , from , to , infinity = Number.MAX_VALUE;
step1();
step2();
return getPath();
// Initialization
function step1() {
var selectFrom=g.command("sql","select from V where @rid ="+ ridFrom);
var selectTo=g.command("sql","select from V where @rid ="+ ridTo);
if(selectFrom.length>0 && selectTo.length>0){
from=selectFrom[0];
to=selectTo[0];
S.push(from);
var selectAll=g.command("sql","select from V");
for (i=0;i<selectAll.length;i++) {
if (selectAll[i].getId()!=from.getId())
T.push(selectAll[i]);
}
var index=1;
for (i=0;i<selectAll.length;i++) {
var id = selectAll[i].getId();
if (selectAll[i].getId()!= from.getId()) {
id_weigth[index] = {id:id,weigth:infinity};
index++;
}
else
id_weigth[0] = {id:id,weigth:0};
}
setWeigth_Direction(from);
}
}
// Assignment permanent label
function step2(){
var stop = true;
do {
stop = true;
for (i=0;i<T.length;i++) {
var id = T[i].getId();
for (j=0;j<id_weigth.length;j++) {
if (id_weigth[j].id==id) {
if (id_weigth[j].weigth != infinity){
stop = false;
}
}
}
}
if (stop == true)
break;
else {
var index2 = 0; minWeigth = 0; j = null;
for (i=0;i<T.length;i++) {
var id = T[i].getId();
for (m=0;m<id_weigth.length;m++) {
if (id_weigth[m].id==id) {
if (index2 == 0) {
minWeigth = id_weigth[m].weigth;
index2++;
j = T[i];
}
else if (id_weigth[m].weigth < minWeigth) {
minWeigth = id_weigth[m].weigth;
j = T[i];
}
}
}
}
T.splice(getPositionInT(j.getId()),1);
S.push(j);
if (T.length == 0)
break;
else
step3(j);
}
} while (stop == false);
}
// Assignment temporary label
function step3(j) {
setWeigth_Direction(j);
}
function setWeigth(vertex,direction1,direction2) {
var edges=g.command("sql","select expand(" + direction1+"E()) from "+ vertex.getId());
for(m=0;m<edges.length;m++){
var myEdge=edges[m];;
var idEdge = myEdge.getId().toString();
var validEdge=true;
for (s=0;s<listEdges.length;s++) {
if(listEdges[s]==idEdge)
validEdge=false;
}
if(validEdge==true){
var myWeigth = myEdge.getProperty(property);
var myVertex=g.command("sql","select expand("+ direction2 + ") from " +myEdge.getId());
var id = myVertex[0].getId();
if(vertex!=from){
for (p=0;p<T.length;p++) {
if (T[p].getId()==id) {
var id_weight_i = getId_Weigth(id);
var id_weight_j = getId_Weigth(j.getId());
var weigthi = id_weight_i.weigth;
var weigthj = id_weight_j.weigth;
if (weigthi > weigthj + myWeigth) {
id_weight_i.weigth=weigthj + myWeigth;
id_weight_i.previous=vertex;
}
}
}
}
else{
for (q=0;q<id_weigth.length;q++) {
if (id_weigth[q].id==id) {
id_weigth[q].weigth=myWeigth;
id_weigth[q].previous=vertex;
}
}
}
}
}
}
function getId_Weigth(id) {
for (l=0;l<id_weigth.length;l++) {
if (id_weigth[l].id==id)
return id_weigth[l];
}
return null;
}
function getPath(){
var validPath = true, temp = [], path = [];
temp.push(to);
var npm = getId_Weigth(to.getId());
var v = npm.previous;
while (v != from) {
temp.push(v);
if (v == null) {
validPath = false;
break;
}
npm = getId_Weigth(v.getId());
v = npm.previous;
}
if (validPath == true) {
temp.push(from);
for (i = temp.length - 1; i >= 0; i--)
path.push(temp[i]);
}
return path;
}
function setWeigth_Direction(vertex){
if (direction == "both"){
setWeigth(vertex,"in","out");
setWeigth(vertex,"out","in");
}
else if (direction == "in")
setWeigth(vertex,"in","out");
else
setWeigth(vertex,"out","in");
}
function getPositionInT(id){
for (l=0;l<T.length;l++) {
if(T[l].getId()==id)
return l;
}
return null;
}
我创建了这个类来查找dijkstra路径，其中包括按rid编号排除特定边列表的选项 dijkstraexc.java
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.tinkerpop.blueprints.Direction;
import com.tinkerpop.blueprints.Edge;
import com.tinkerpop.blueprints.Vertex;
import com.tinkerpop.blueprints.impls.orient.OrientGraph;
public class DijkstraExcl {
private OrientGraph g; //grafh DB
private Set<String> S; //visited rids
private Set<String> T; //to visit rids
private Map<String,Integer> f; //f(i) < @rid, weight_to_get_to_@rid >
private Map<String,String> J; //J(i) < @rid, previous_node_in_the_shortest_path >
private String eClass; //edge class to use
private String prop; //weight property to use on the edge
public DijkstraExcl(OrientGraph g, String e, String p){
this.g= g;
this.eClass = e;
this.prop = p;
S = new HashSet<String>();
T = new HashSet<String>();
f = new HashMap<String,Integer>();
J = new HashMap<String,String>();
}
//private methods
// (Vertex start_vertex, Vertex dest_vertex, Direction.IN/OUT/BOTH, Set of edge rids to exclude)
private void findPath(Vertex startV, Vertex endV, Direction dir, Set<String> excludeEdgeRids){
//init
S.clear();
T.clear();
f.clear();
J.clear();
//step1
Iterator<Vertex> vertici = g.getVertices().iterator();
while(vertici.hasNext()){
Vertex ver = vertici.next();
f.put(ver.getId().toString(), Integer.MAX_VALUE);
T.add(ver.getId().toString());
}
f.put(startV.getId().toString(), 0); //f(startV) = 0
J.put(startV.getId().toString(), null); //J(startV) = null
T.remove(startV.getId().toString()); //startV visited => removed from T
S.add(startV.getId().toString()); // and added in S
Iterator<Vertex> near = startV.getVertices(dir, eClass).iterator();
while(near.hasNext()){
Vertex vicino = near.next();
J.put(vicino.getId().toString(), startV.getId().toString()); //J(i) = startV
f.put(vicino.getId().toString(), weight(startV.getId().toString(), vicino.getId().toString(),dir,excludeEdgeRids)); //f(i) = weight(startV, i)
}
//step2
Boolean cont = false;
Iterator<String> t = T.iterator();
while(t.hasNext()){
String i = t.next();
if(f.get(i)!=Integer.MAX_VALUE){
cont = true;
}
}
while(cont){
String j = startV.getId().toString();
Integer ff = Integer.MAX_VALUE;
t = T.iterator();
while(t.hasNext()){
String i = t.next();
if(f.get(i)<=ff){
ff = f.get(i);
j = i;
}
}
T.remove(j);
S.add(j);
if(T.isEmpty()){
break;
}
//step3
near = g.getVertex(j).getVertices(dir, eClass).iterator();
while(near.hasNext()){
Vertex vic = near.next();
String i = vic.getId().toString();
if( (T.contains(i)) && (f.get(i) > (f.get(j) + weight(j,i,dir,excludeEdgeRids))) ){
if(weight(j,i,dir,excludeEdgeRids)==Integer.MAX_VALUE){
f.put(i, Integer.MAX_VALUE);
}else{
f.put(i, (f.get(j) + weight(j,i,dir,excludeEdgeRids)));
}
J.put(i, j);
}
}
//shall we continue?
cont = false;
t = T.iterator();
while(t.hasNext()){
String i = t.next();
if(f.get(i)!=Integer.MAX_VALUE){
cont = true;
}
}
}
}
private int weight(String rid_a, String rid_b, Direction dir, Set<String> excl){ //in case of multiple/duplicate edges return the lightest
Integer d = Integer.MAX_VALUE;
Integer dd;
rid_b = "v["+rid_b+"]";
if(excl==null){
excl = new HashSet<String>();
}
Vertex a = g.getVertex(rid_a);
Iterator<Edge> eS = a.getEdges(dir, eClass).iterator();
Set<Edge> goodEdges = new HashSet<Edge>();
while(eS.hasNext()){
Edge e = eS.next();
if((e.getProperty("out").toString().equals(rid_b) || e.getProperty("in").toString().equals(rid_b)) && !excl.contains(e.getId().toString())){
goodEdges.add(e);
}
}
Iterator<Edge> edges= goodEdges.iterator();
while(edges.hasNext()){
Edge e=edges.next();
dd = e.getProperty(prop);
if(dd<d){
d=dd;
}
}
return d;
}
//public methods
public List<Vertex> getPath (Vertex startV, Vertex endV, Direction dir, Set<String> exclECl){
String j,i;
List<Vertex> ppp = new ArrayList<Vertex>();
List<Vertex> path = new ArrayList<Vertex>();
findPath(startV, endV, dir, exclECl);
i = endV.getId().toString();
path.add(endV);
if(f.get(endV.getId().toString()) == Integer.MAX_VALUE){
return null;
}
while(!i.equals(startV.getId().toString())){
j = J.get(i);
if(j == null){
return null;
}
path.add(g.getVertex(j));
i = j;
}
for(int a=0, b=path.size()-1;a<path.size();a++, b--){
ppp.add(a, path.get(b));
}
return ppp;
}
public List<String> getPathString (Vertex startV, Vertex endV, Direction dir, Set<String> exclECl){
List<String> pathS = new ArrayList<String>();
List<Vertex> path = getPath(startV, endV, dir, exclECl);
if(path == null){
return null;
}
for(Vertex v : path){
pathS.add(v.getId().toString());
}
return pathS;
}
public Integer getWeight(Vertex startV, Vertex endV, Direction dir, Set<String> exclECl){
findPath(startV, endV, dir,exclECl);
return f.get(endV.getId().toString());
}
}
我认为您必须用javascript编写一个函数来忽略一些问题edge@AlessandroRota你能给我举个例子吗？我会尽快给你举个例子Hi，你需要通过@rid忽略一些特定的边还是通过边类忽略一些特定的边？谢谢你的回答，但是你能给我更多的细节或者更多的解释吗。谢谢你的回答。我试着用你的三种方法。但我有问题。getPath返回null，getPathString也返回null。getWeight返回2147483647Integer.Max_值。我在Dijkstraexc类的函数getPath中使用了'Log'显示fHashMap值。然后我发现fHashMap的所有值都是2147483647Integer.Max_velue，所以我认为当FindPath或其他方法调用时，weight总是返回2147483647Integer.Max_velue。为什么我的结果不正确？你能给我更多的建议吗？我的电子课堂是“路径”，我的权重属性是“距离”，我已经通过Orientdb的dijkstra测试，它可以工作。所以我认为我的数据库中的信息没有错。你能给我一个图表的例子吗？你是如何调用这些方法的？谢谢伊万：谢谢你的迅速回复。我不知道如何上传图片的评论，你能告诉我如何向你发送我的图形结构。顺便说一句，我正在调用方法，就像所有位于顶部的主测试一样。但是，相应地更改方法的参数，以删除我的顶点类、边类和权重属性。请注意，要获得与orient内置函数相同的结果，必须将遍历方向设置为OUT，并注释掉每个ex.add；呼叫再见，伊万，非常感谢你的回答。我用你的js代码创建了函数，因为Dijkstra_被忽略了，我尝试了函数代码select expandresult from select Dijkstra_Ignored12:6,12:11，distance，out，[13:0]作为结果代码，但结果是[12:6,12:7,12:10,12:11]，与我使用普通Dijkstra时的结果相同。正确答案应该是[12:6,12:8,12:10,12:11]。但结果并不正确。您可以在我编辑的主题上查看我的数据。这是我的图片哇。非常感谢，代码运行良好，为我的所有图形示例提供了正确的结果。
public class test_dijkstra {
public static void main(String[] args) {
String nomeDb = "dijkstra_test";
try {
OServerAdmin serverAdmin = new OServerAdmin("remote:localhost/"+nomeDb).connect("root", "root");
if(serverAdmin.existsDatabase()){ // il db esiste
//connessione a db
OrientGraph g = new OrientGraph("remote:localhost/"+nomeDb);
DijkstraExcl d = new DijkstraExcl(g, "arco", "peso");
Set<String> ex =new HashSet<String>();
//------------------------------------------------
Vertex start = g.getVertex("#9:0");
Vertex end = g.getVertex("#9:5");
ex.add("#12:4");
Direction direction = Direction.BOTH;
System.out.println(d.getPath(start,end,direction,ex));
System.out.println(d.getPathString(start,end,direction,ex));
System.out.println(d.getWeight(start,end,direction,ex));
//------------------------------------------------
//chiude db
g.shutdown();
}
else{
System.out.println("Il database '"+ nomeDb + "' non esiste");
}
serverAdmin.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
[v[#9:0], v[#9:1], v[#9:2], v[#9:4], v[#9:5]]
[#9:0, #9:1, #9:2, #9:4, #9:5]
10