[netcdf-java] Multi-threading and gridsets - help

• To: "netcdf-java@xxxxxxxxxxxxxxxx" <netcdf-java@xxxxxxxxxxxxxxxx>
• Subject: [netcdf-java] Multi-threading and gridsets - help
• From: Steven Hawes <steven.hawes@xxxxxxxxxxxxx>
• Date: Fri, 28 Jul 2017 06:49:06 +0000

Hello,

I’m having trouble with threading and using GridDataSets. I was wondering what 
I am doing wrong.

Using the tutorial I initially create the file cache as such

NetcdfDataset.initNetcdfFileCache(...)

Then I’m opening the grid data set using the open command, which uses the 
NetcdfDataset.aquire… to use the file cache

GridDataset gds = ucar.nc2.dt.grid.GridDataset.open(location);

Then when I want to read the data from a grid I use:

Array data  = grid.readDataSlice(0, 0, xy[1], xy[0])

However, when running this code with threads, it throws out this exception 
(works fine with one thread). It appears to access 
ucar.unidata.io.RandomAccessFile.read, which I thought the cache prevented it 
from using?

java.io.IOException: java.lang.ArrayIndexOutOfBoundsException: 131006
at ucar.nc2.dt.grid.GeoGrid.readDataSlice(GeoGrid.java:609)
at ucar.nc2.dt.grid.GeoGrid.readDataSlice(GeoGrid.java:517)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 131006
at ucar.unidata.io.RandomAccessFile.read(RandomAccessFile.java:643)
at ucar.unidata.io.RandomAccessFile.readShort(RandomAccessFile.java:1115)
at ucar.unidata.io.RandomAccessFile.readShort(RandomAccessFile.java:1137)
at ucar.nc2.iosp.IospHelper.readData(IospHelper.java:123)
at ucar.nc2.iosp.IospHelper.readDataFill(IospHelper.java:79)
at ucar.nc2.iosp.netcdf3.N3raf.readData(N3raf.java:63)
at ucar.nc2.iosp.netcdf3.N3iosp.readData(N3iosp.java:484)
at ucar.nc2.NetcdfFile.readData(NetcdfFile.java:2020)
at ucar.nc2.Variable.reallyRead(Variable.java:913)
at ucar.nc2.Variable._read(Variable.java:898)
at ucar.nc2.Variable.read(Variable.java:709)
at ucar.nc2.dataset.VariableDS.reallyRead(VariableDS.java:557)
at ucar.nc2.dataset.VariableDS._read(VariableDS.java:537)
at ucar.nc2.SectionReader.reallyRead(SectionReader.java:75)
at ucar.nc2.dataset.VariableDS._read(VariableDS.java:537)
at ucar.nc2.Variable.read(Variable.java:709)
at ucar.nc2.Variable.read(Variable.java:655)
at ucar.nc2.dt.grid.GeoGrid.readDataSlice(GeoGrid.java:606)
at ucar.nc2.dt.grid.GeoGrid.readDataSlice(GeoGrid.java:517)

Is there something I am missing?
STEVE HAWES | PhD Candidate
Coastal & Marine Ecosystems Group (CMEG) | School of Life & Environmental 
Sciences (SOLES) | Faculty of Science
THE UNIVERSITY OF SYDNEY
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  • Re: [netcdf-java] Multi-threading and gridsets - help
    • From: Christian Ward-Garrison