Error raised when no data exists in specified time range

[joacorapela]

There is a problem in the function aeon.query.pelletdata for longer start times, but not for shorter ones.
The code bellow runs well with a shorter star_time=600 but raises an error for a larger start_time=14000

$ python doBugReport061521.py --start_time=16000
ValueError: No objects to concatenate
/nfs/ghome/live/rapela/anaconda3/envs/aeon_env/lib/python3.9/site-packages/pandas/core/reshape/concat.py(342)init()
340
341 if len(objs) == 0:
--> 342 raise ValueError("No objects to concatenate")

import sys
import pdb
import datetime
import argparse

import aeon.preprocess.utils
from aeon.query import exp0_api
                                                                                                                                                                                                                                                                                  

def main(argv):
    parser = argparse.ArgumentParser()
    parser.add_argument("--root", help="Root path for data access", default="/ceph/aeon/test2/experiment0.1")
    parser.add_argument("--session", help="Session index", default=3, type=int)
    parser.add_argument("--start_time", help="Start time (sec)", default=0.0, type=float)
    parser.add_argument("--duration", help="Duration (sec)", default=14000.0, type=float)
    parser.add_argument("--patch_name", help="Patch name", default="Patch2")

    args = parser.parse_args()

    root = args.root
    session = args.session
    t0_relative = args.start_time
    requested_duration = args.duration
    tf_relative = args.start_time+args.duration
    patch_name = args.patch_name

    metadata = exp0_api.sessiondata(root)
    metadata = metadata[metadata.id.str.startswith('BAA')]
    metadata = aeon.preprocess.utils.getPairedEvents(metadata=metadata)
    metadata = exp0_api.sessionduration(metadata)

    session_duration_sec = metadata.iloc[session].duration.total_seconds()
    if requested_duration>session_duration_sec:
        raise ValueError("Requested duration {:f} exceeds the session duration {:f}".format(requested_duration, session_duration_sec))
    print("Session duration {:f}".format(session_duration_sec))

    session_start = metadata.index[session]
    t0_absolute = session_start + datetime.timedelta(seconds=t0_relative)
    tf_absolute = session_start + datetime.timedelta(seconds=tf_relative)
    pellet_vals = exp0_api.pelletdata(root, patch_name, start=t0_absolute, end=tf_absolute)

    pdb.set_trace()

if __name__=="__main__":
    main(sys.argv)

[glopesdev]

At first glance this means that no data was found inside the specified interval. I do agree that it should return an empty data frame instead of throwing an error. Will fix it soon.

[joacorapela]

Thanks for your quick reply @glopesdev
Note that the requested start_time=14000 and duration=600 are within the session duration

Session duration 15548.271639

[glopesdev]

Yes, sorry what I meant when I said "no data" is that maybe no pellets were delivered during that time, so in that case there would be no events to report.

[joacorapela]

At other times there are no pellets delivered but I did not get an error.

[glopesdev]

This turned out to be a more general issue around querying time ranges where no data has been recorded (e.g. in case of a crash). I'm pushing a fix now on the exp01-api branch.