TGBT15A_915_99 - Detailed fftshift and scale tests for incoherent modes


  • Find best combination of fftshift and vegas.scale to eliminate/minimize FFT overflow artifacts and get good output levels from VEGAS.


Session begins at 09:45
  • Switched to Justin's VPM branch
  • Set iniitial fftshift to 0x5555555f and vegas.scale to 1000. Will use GUPPI when possible to verify data. Initial guppi.scale set to 1.5.
  • Using IncoherentFFTSHIFTTest SB
    • SB submitted at 09:47
    • VEGAS was slow to activate and SB aborted. Resubmitting at 09:51
    • VEGAS aborted again with message "failed to start HPC subprocess". Manager reports "hpc_process: unable to open pipe: No such device or address"
    • Restarting VEGAS manager on vegas-hpc1
    • Resubmitting SB at 09:57
    • Failed again. Manager logs seem to report an issue with registering the BankAMgr. Calling Justin.
    • Justin will try to rebuild and reinstall the manager.
    • Resubmitting SB at 10:07
    • Still got an abort but trying to run scan anyway.
    • Scan #4 - No VEGAS data. GUPPI scale is high.
    • Still aborted on next scan. Maybe using GUPPI is the issue? Seems unlikely but will give it a try with just VEGAS.
    • Still failing after many attempts. Trying to run the VPM-TestManyModes SB, which ran yesterday.
    • No difference.
    • Justin reverted the manager back to the previous version (no support for 32-channel modes). This worked yesterday, so let's see if it helps.
    • Well it started running, but not in pulsar mode...aborting.
    • Got it to configure for pulsar mode, but still aborted. Put guppi_daq in MONITOR and packets are flowing, so it doesn't seem to be the ROACH.
    • Will try resetting ROACH. That is the last thing I can think of.
    • No change. Confirmed that spec line modes run.
    • Tried a different fftshift value, in case that was doing something to the ROACH. No difference.
    • Trying to do the complete switch_vegas routine again. No difference.


Session was a complete wash. -- RyanLynch - 2017-06-29

This topic: CICADA > WebHome > GreenBankSpectrometer > CICADAGreenBankSpectrometerCommissioningLogs > CICADAGreenBankSpectrometer2017Jun29
Topic revision: 2017-06-29, RyanLynch
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