def interpolateToSecond(timeData: TimeData, inplace: bool = True) -> TimeData:
"""Interpolate data to be on the second
Some formats of time data (e.g. SPAM) do not start on the second with their sampling. This method interpolates so that sampling starts on the second and improves interoperability with other recording formats.
Parameters
----------
timeData : TimeData
Time data to interpolate onto the second
inplace : bool, optional
Whether to do the interpolation inplace or not. Default is True.
Returns
-------
TimeData
Time data interpolated to start on the second
"""
startTimeInterp, numSamplesInterp, dataInterp = interpolateToSecondData(
timeData.data, timeData.sampleFreq, timeData.startTime
)
if not inplace:
timeData = timeData.copy()
timeData.numSamples = numSamplesInterp
timeData.startTime = startTimeInterp
# calculate end timeEnd
timeData.stopTime = timeData.startTime + timedelta(
seconds=(1.0 / timeData.sampleFreq) * (timeData.numSamples - 1)
)
timeData.data = dataInterp
timeData.addComment(
"Time data interpolated to nearest second. New start time {}, new end time {}, new number of samples {} ".format(
timeData.startTime, timeData.stopTime, timeData.numSamples
)
)
return timeData
def resample(timeData: TimeData, resampFreq: float, inplace: bool = True) -> TimeData:
"""Resample time data
Parameters
----------
timeData : TimeData
timeData to filter
resampFreq : float
The frequency to resample to
inplace : bool, optional
Whether to manipulate the data inplace
Returns
-------
TimeData
Filtered time data
"""
origFreq = timeData.sampleFreq
if not inplace:
timeData = timeData.copy()
timeData.data = resampleData(timeData.data, timeData.sampleFreq, resampFreq)
# update the time info
timeData.sampleFreq = resampFreq
timeData.numSamples = timeData.data[timeData.chans[0]].size
timeData.stopTime = timeData.startTime + timedelta(
seconds=(1.0 / timeData.sampleFreq) * (timeData.numSamples - 1)
)
timeData.addComment(
"Time data resampled from {:.6f} Hz to {:.6f} Hz".format(origFreq, resampFreq)
)
return timeData
def write(self, headers: Dict, chanHeaders: List, chanMap: Dict,
timeData: TimeData, **kwargs):
"""Write out the header file
Parameters
----------
headers : Dict
Dictionary of headers
chanHeaders : List
List of channel headers
chanMap : Dict
Maps channel to index for chanHeaders
timeData : TimeData
Time series data as TimeData object
"""
# set global headers for keyword arguments
headers = self.setGlobalHeadersFromKeywords(headers, kwargs)
# set channel headers for keyword arguments
chanHeaders = self.setChanHeadersFromKeywords(chanHeaders, kwargs)
# now overwrite the options by checking the TimeData object
# number of samples and sample frequency
# Current method favours the time data object
chans = sorted(list(timeData.chans))
dataSizes = []
for c in chans:
dataSizes.append(timeData.data[c].size)
if min(dataSizes) != max(dataSizes):
self.printWarning(
"Channels do not have the same number of samples: {} - {}".
format(", ".join(chans), ", ".join(dataSizes)))
self.printWarning(
"Only the smallest number of samples will be written out")
numSamples = min(dataSizes)
if headers["num_samples"] != numSamples:
self.printWarning(
"Number of samples {} in headers does not match number of samples in TimeData object {}. TimeData info will be used."
.format(headers["num_samples"], numSamples))
headers["num_samples"] = numSamples
timeData.numSamples = numSamples
# sample freq
if headers["sample_freq"] != timeData.sampleFreq:
self.printWarning(
"Sample frequency of {} Hz in headers does not match {} Hz in TimeData object"
.format(headers["sample_freq"], timeData.sampleFreq))
self.printWarning(
"Sample frequency in TimeData object will be used")
headers["sample_freq"] = timeData.sampleFreq
# deal with start and end time and create datetime objects
# the start time does not change on resampling, only the end time
datetimeStart = datetime.strptime(
"{} {}".format(headers["start_date"], headers["start_time"]),
"%Y-%m-%d %H:%M:%S.%f",
)
datetimeStop = datetime.strptime(
"{} {}".format(headers["stop_date"], headers["stop_time"]),
"%Y-%m-%d %H:%M:%S.%f",
)
# now let's compare to the time data
if datetimeStart != timeData.startTime:
self.printWarning(
"Start in headers {} does not match that in TimeData object {}. TimeData start time will be used"
.format(datetimeStart, timeData.startTime))
datetimeStart = timeData.startTime
if datetimeStop != timeData.stopTime:
self.printWarning(
"Stop in headers {} does not match that in TimeData object {}. TimeData stop time will be used"
.format(datetimeStop, timeData.stopTime))
datetimeStop = timeData.stopTime
# now recalculate datetime using the number of samples and compare again
datetimeRecalc = self.calcStopDateTime(timeData.sampleFreq, numSamples,
datetimeStart)
if datetimeRecalc != datetimeStop:
self.printWarning(
"Note, discrepancy between stop time in given headers and those calculated from data"
)
self.printWarning(
"Causes of this might be resampling or interpolation processes and the limiting of data"
)
self.printWarning(
"If no resampling, interpolation or limiting of data has been performed, please check all times"
)
self.printWarning(
"Stop time {} calculated from data will be used instead of that in data {}"
.format(datetimeRecalc, datetimeStop))
datetimeStop = datetimeRecalc
headers["start_date"] = datetimeStart.strftime("%Y-%m-%d")
headers["start_time"] = datetimeStart.strftime("%H:%M:%S.%f")
headers["stop_date"] = datetimeStop.strftime("%Y-%m-%d")
headers["stop_time"] = datetimeStop.strftime("%H:%M:%S.%f")
# now update all the chan headers and limit data to numSamples
for c in chans:
timeData.data[c] = timeData.data[c][:numSamples]
cIndex = chanMap[c]
chanHeaders[cIndex]["num_samples"] = headers["num_samples"]
chanHeaders[cIndex]["sample_freq"] = headers["sample_freq"]
chanHeaders[cIndex]["start_date"] = headers["start_date"]
chanHeaders[cIndex]["start_time"] = headers["start_time"]
chanHeaders[cIndex]["stop_date"] = headers["stop_date"]
chanHeaders[cIndex]["stop_time"] = headers["stop_time"]
# finally, check the number of measurement channels
headers["meas_channels"] = len(chans)
# now write out the headers and save to class variables
self.writeHeaders(headers, chans, chanMap, chanHeaders)
self.headers = headers
self.chans = chans
self.chanMap = chanMap
self.chanHeaders = chanHeaders
# write out comment file
self.writeComments(timeData.comments)
# write out the data files
self.writeDataFiles(chans, timeData)
