Cycle Detection in Graph

[Amit Kumar Mondal]

Hello all,

I am trying to detect existence of cycles in a JointJS directed graph. I tried the following approach:

           function checkForCycleExistence() {

              var visited = [];

              var level = 0;

              var isCycleExists;

              var _elements = graph.getElements();

             for (var i = 0; i < _elements.length; i++) {

                   var elem = _elements[i];

                       if ((graph.getPredecessors(elem).length > 0) && !elem.isLink()

                                 && hasCycle(elem, visited, level)) {

                           isCycleExists = true;

                          break;

                 }

              }

              if (isCycleExists) {

                   top.jsniShowCycleExistenceError();

              }

              return isCycleExists;

          }

     

        function hasCycle(comp, visited, level) {

              var neighbors = graph.getNeighbors(comp, {

                     outbound : true

        }), i;

                if (visited.indexOf(comp.id) > -1)

                     return true;

           visited.push(comp.id);

                for (i = 0; i < neighbors.length; i++)

                 if (hasCycle(neighbors[i], visited.slice(), ++level))

                          return true;

                return false;

        }

I tried it with many examples and it seems it can find cycles in most of the graphs except in some trivial ones where the graph does not contain any cycle. For instance, 

A--->B, A--->C, C--->D, D--->B

or 

A--->B, A--->C and C--->B

It would be really helpful if anyone can help me in this.

[Amit Kumar Mondal]

http://stackoverflow.com/questions/39431889/jointjs-cycle-detection