GUPPI

The Green Bank Ultimate Pulsar Processing Instrument (GUPPI) was previously the main pulsar backend for the GBT. It is retired as of January 2021 and has been replaced by VEGAS Pulsar Modes (VPM).

Transitioning from GUPPI to VPM

Experienced pulsar observers will recognize that GUPPI and VPM observing are very similar, especially the parameters used in scheduling blocks. The following table summarizes the similarities and some differences between GUPPI and VPM.

Astrid: Most "guppi." parameters can be replaced with "vegas.". The exceptions are guppi.datadisk, which has no VPM equivalent.

File names: VPM output file names include a new element, the number of seconds after midnight UTC. vegas_<MJD>_<secUTC>_<sourceName>_<scanNumber>_<fileNumber>.fits vegas_<MJD>_<secUTC>_<sourceName>_cal_<scanNumber>_<fileNumber>.fits

The table below can be used a cheat-sheet for navigating between some common GUPPI and VPM tasks.

Table 25 Quick Reference for Transitioning from GUPPI to VPM

GUPPI Tool or Procedure	VEGAS Tool or Procedure	Notes
guppi_adc_hist	VEGAS Data Monitor	Data monitor updates continuously; No need to pause a scheduling block to check ADC levels.
guppi_status	vpmStatus	Must be run from the appropriate VEGAS HPC (e.g. vegas-hpc11).
guppi_gpu_status	vpmHPCStatus	Can be run from any computer.
guppi_monitor	vpmMonitor	Web interface is preferred; Must be run from the appropriate VEGAS HPC (e.g. vegas-hpc11)
guppi_offsets	vpmTimingOffsets.py	Used to find mode-dependent timing offsets.
www.gb.nrao.edu/guppi	www.gb.nrao.edu/vpm	Firefox is recommended (Google Chrome does not always update properly)
www.gb.nrao.edu/guppi/guppi_monitor	www.gb.nrao.edu/vpm/vpm_monitor	Firefox is recommended (Google Chrome does not always update properly)
/data1/<userName>/<projectID>/<date> /data2/<userName>/<projectID>/<date>	*/<projectID>/VEGAS/<bankID>	Output directory for incoherent dedispersion modes.
/data/gpu/partial/<gpuNum>/	*/<projectID>/VEGAS_CODD/<bankID>	Output directory for coherent dedispersion modes.

Note

The asterisk denotes a shortcut for /lustre/gbtdata.