Hi Christian,
Thanks for clarifying that, seems I can get away without cacheing. From the
tutorial it seemed it was required for multi-threading. I’ve found the error of
my ways also, not related to netcdf, as I was using am utable index to access
the GeoGrid. Once I made this immutable (I’m coding my app in Scala), it seems
to have become thread safe.
I’m a big fan of these GridDataset libraries, makes accessing oceanography
netcdf files a breeze!
STEVE HAWES | PhD Candidate
Coastal & Marine Ecosystems Group (CMEG) | School of Life & Environmental
Sciences (SOLES) | Faculty of Science
THE UNIVERSITY OF SYDNEY
Rm 114, Edgeworth-David Bldg A11 | The University of Sydney | NSW | 2006
M +61 439 881 324
E steven.hawes@xxxxxxxxxxxxx<mailto:firstname.surname@xxxxxxxxxxxxx> | W
sydney.edu.au<http://sydney.edu.au>
Tweets @stevehawes
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On 29 Jul 2017, at 4:20 AM, Christian Ward-Garrison
<cwardgar@xxxxxxxx<mailto:cwardgar@xxxxxxxx>> wrote:
Hi Steven,
Are you sure you need NetcdfDataset.initNetcdfFileCache() ? It is generally
used when you expect to access the same file multiple times and you don't want
to re-read it and re-construct its metadata each time. Is that your use case?
As for the threading issue, can you provide a complete example that
demonstrates it, including code and resources?
Thanks,
Christian
On Fri, Jul 28, 2017 at 12:49 AM, Steven Hawes
<steven.hawes@xxxxxxxxxxxxx<mailto:steven.hawes@xxxxxxxxxxxxx>> wrote:
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<http://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<http://ucar.unidata.io/>.RandomAccessFile.read(RandomAccessFile.java:643)
at
ucar.unidata.io<http://ucar.unidata.io/>.RandomAccessFile.readShort(RandomAccessFile.java:1115)
at
ucar.unidata.io<http://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
Rm 114, Edgeworth-David Bldg A11 | The University of Sydney | NSW | 2006
M +61 439 881 324<tel:+61%20439%20881%20324>
E steven.hawes@xxxxxxxxxxxxx<mailto:firstname.surname@xxxxxxxxxxxxx> | W
sydney.edu.au<http://sydney.edu.au/>
Tweets @stevehawes
INSPIRED – the Campaign to support the University of Sydney
sydney.edu.au/inspired<http://inspired.sydney.edu.au/>
CRICOS 00026A
This email plus any attachments to it are confidential. Any unauthorised use is
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