A DifX software correlator for the RAEGE project

For the RAEGE network to operate autonomously the ERDF project YNART (Infrastructures for updating the radio telescopes at Yebes Observatory) have provided a
scalable and flexible software VLBI correlator based on a High Performance Cluster. The base design is intended
for the correlation of VGOS data from four stations with a weekly observation cadence, but the design allows
for the easy addition of more compute nodes to handle larger sessions in terms of number of baselines. This
correlator is now completed and ready to operate. Although its main focus is the RAEGE network, some of the
available time can be offered to the geodetic VLBI community. Here we present the correlator, its architecture
and the hardware that has been used together with the tests carried out to check its correct functioning (real VLBI
sessions) and benchmarking analysis. We have tested different working scenarios as a function of the number of
threads and we have explored the execution time when increasing the number of stations from 4 to 10.