Running on ELKI the OPTICS and DeLiClu algorithms I get only the cluster object order file as result. How can I get the clusters list and the mapping among points and the respective cluster?
The OPTICS class does not (by design) produce clusters.
Instead, it produces the cluster order as defined by OPTICS.
If you want to extract partitions from the cluster order, please use the class OPTICSXi, which implements the main extraction method (adding the xi parameter) discussed in the OPTICS paper. This method can be used with either OPTICS or DeLiClu.
There are other alternatives to extract such partitions, but they have not yet been contributed to ELKI.