reset
Class: matlab.io.datastore.sdidatastore
Package: matlab.io.datastore
Reset the read position
Syntax
sdi_ds.reset
Description
sdi_ds.reset
resets the read position for the
matlab.io.datastore.sdidatastore
, sdi_ds
, to
the beginning.
Examples
Process Signal Data Using a matlab.io.datastore.sdidatastore
A matlab.io.datastore.sdidatastore
references signal data in the Simulation Data Inspector repository. When the signal is too large to fit into memory, you can use the matlab.io.datastore.sdidatastore
to incrementally process the data manually or to create a tall timetable for the signal that handles the incremental processing for you. This example shows how to process data using a matlab.io.datastore.sdidatastore
.
Create a matlab.io.datastore.sdidatastore
for a Signal
Simulate the sldemo_fuelsys
model, which is configured to log several signals, to create data in the Simulation Data Inspector repository.
sim('sldemo_fuelsys')
Use the Simulation Data Inspector programmatic interface to get the signal ID for the signal.
runCount = Simulink.sdi.getRunCount; latestRunID = Simulink.sdi.getRunIDByIndex(runCount); latestRun = Simulink.sdi.getRun(latestRunID); speedSigID = latestRun.getSignalIDByIndex(4);
Use the signal ID to create a matlab.io.datastore.sdidatastore
for the speed
signal.
speedSDIds = matlab.io.datastore.sdidatastore(speedSigID);
Verify the Contents of the Datastore
Check the Name
property of the matlab.io.datastore.sdidatastore
to verify that it matches your expectations.
speedSDIds.Name
ans = 'map'
You can also use the preview
method to check that the first ten samples in the signal look correct.
speedSDIds.preview
ans=10×1 timetable
Time Data
______________ _______
0 sec 0.589
0.00056199 sec 0.58772
0.0033719 sec 0.58148
0.01 sec 0.56765
0.02 sec 0.54897
0.03 sec 0.53264
0.04 sec 0.51837
0.05 sec 0.50594
0.055328 sec 0.5
0.055328 sec 0.5
Process Signal Data with the matlab.io.datastore.sdidatastore
When your signal is too large to fit into memory, you can use the readData
method to read chunks of data from the Simulation Data Inspector repository to incrementally process your data. Use the hasdata
method as the condition for a while loop to incrementally process the whole signal. For example, find the maximum signal value.
latestMax = []; while speedSDIds.hasdata speedChunk = speedSDIds.read; speedChunkData = speedChunk.Data; latestMax = max([speedChunkData; latestMax]); end latestMax
latestMax = 0.8897
On each read operation, the read
method updates the read position for the start of the next read operation. After reading some or all of the matlab.io.datastore.sdidatastore
, you can reset the read position to start again from the beginning of the signal.
speedSDIds.reset
Process Signal Data in Memory
When the signal referenced by your matlab.io.datastore.sdidatastore
fits into memory, you can use the readall
method to read all the signal data into memory for processing, rather than reading and processing the data incrementally with the read
method. The readall
method returns a timetable
with all the signal data.
speedTimetable = speedSDIds.readall; speedMax = max(speedTimetable.Data)
speedMax = 0.8897
Version History
Introduced in R2017b
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