FilterByTime v1¶

FilterByTime dialog.

Table of Contents

Summary
Properties
Description
- Comparing with other event filtering algorithms
Usage
Source

Summary ¶

This algorithm filters out events from an EventWorkspace that are not between given start and stop times.

Properties ¶

Name	Direction	Type	Default	Description
InputWorkspace	Input	EventWorkspace	Mandatory	An input event workspace
OutputWorkspace	Output	EventWorkspace	Mandatory	The name to use for the output workspace
StartTime	Input	number	0	The start time, in seconds, since the start of the run. Events before this time are filtered out. The time of the first pulse (i.e. the first entry in the ProtonCharge sample log) is used as the zero. You can only specify the relative or absolute start/stop times, not both.
StopTime	Input	number	0	The stop time, in seconds, since the start of the run. Events at or after this time are filtered out. The time of the first pulse (i.e. the first entry in the ProtonCharge sample log) is used as the zero. You can only specify the relative or absolute start/stop times, not both.
AbsoluteStartTime	Input	string		Absolute start time; events before this time are filtered out. Specify date and UTC time in ISO8601 format, e.g. 2010-09-14T04:20:12. You can only specify the relative or absolute start/stop times, not both.
AbsoluteStopTime	Input	string		Absolute stop time; events at of after this time are filtered out. Specify date and UTC time in ISO8601 format, e.g. 2010-09-14T04:20:12. You can only specify the relative or absolute start/stop times, not both.

Description ¶

Goes through all events in all EventLists and takes out any events with a PulseTime value not within the range specified.

Sample logs consisting of TimeSeriesProperty‘s are also filtered out according to the same time.
The integrated proton charge of the run is also re-calculated according to the filtered out ProtonCharge pulse log.

You must specify:

Both StartTime and Stop time, or
Both AbsoluteStartTime and AbsoluteStop time.
But not another combination of the four, or the algorithm will abort.

Comparing with other event filtering algorithms ¶

Wiki page Event Filtering has a detailed introduction on event filtering in MantidPlot.

Usage ¶

Example - Using a relative and absolute times

ws = CreateSampleWorkspace("Event",BankPixelWidth=1)
AddTimeSeriesLog(ws, Name="proton_charge", Time="2010-01-01T00:00:00", Value=100)
AddTimeSeriesLog(ws, Name="proton_charge", Time="2010-01-01T00:10:00", Value=100)
AddTimeSeriesLog(ws, Name="proton_charge", Time="2010-01-01T00:20:00", Value=100)
AddTimeSeriesLog(ws, Name="proton_charge", Time="2010-01-01T00:30:00", Value=100)
AddTimeSeriesLog(ws, Name="proton_charge", Time="2010-01-01T00:40:00", Value=15)
AddTimeSeriesLog(ws, Name="proton_charge", Time="2010-01-01T00:50:00", Value=100)

#Extract the first 30 minutes  * 60 = 1800 seconds (roughly half of the data)
wsFiltered = FilterByTime(ws,StartTime=0,StopTime=1800)

#Extract the first 30 minutes  * 60 = 1800 seconds (roughly half of the data)
wsFilteredAbs = FilterByTime(ws,
    AbsoluteStartTime="2010-01-01T00:10:00",
    AbsoluteStopTime="2010-01-01T00:20:00")

print ("The number of events within the relative Filter: %i" % wsFiltered.getNumberEvents())
print ("The number of events within the Aboslute Filter: %i" % wsFilteredAbs.getNumberEvents())
print ("Compared to the number in the unfiltered workspace: %i" % ws.getNumberEvents())

Output:

The number of events within the relative Filter: 950
The number of events within the Aboslute Filter: 315
Compared to the number in the unfiltered workspace: 1900

Categories: Algorithms | Events\EventFiltering