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Re: NetCDF Array to Java byte array, speed issue

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  • Subject: Re: NetCDF Array to Java byte array, speed issue
  • Date: Fri, 25 Oct 2002 19:43:19 -0600
theres not much else to do to speed up the read for now. we will rewrite the library using the java.nio package sometime in the future; preliminary tests suggest we will get a factor of 2 speedup. 

you can extract the byte array through:

  byte[] data = (byte[]) fullA.getStorage();



William Ruddick wrote:


John / Support -
I have a huge 5120x5120 byte array representing a Sataelite image, that I am reading out of a NetCDF file using the 

NetCDF Java Libraries v.2.
It is taking me an average of 10 seconds on a P2 233 Windows 200 machine with 512M ram.
I believe this is taking twice as long as it should be. Do you have any suggestions? 

My code is a follows:


//////////////////////////////////

fullimagebytes = new byte[(int)5120*5120];

ucar.nc2.Variable lVar = cdfFile.findVariable("image");
ucar.ma2.Array fullA = lVar.read(); // This statement takes on average 5 seconds 


ucar.ma2.IndexIterator iter = fullA.getIndexIteratorFast();
int xi = 0;
while (iter.hasNext()) { // This loop takes another 5 seconds on average
fullimagebytes[xi] = iter.getByteNext(); xi++; 
   }

//////////////////////////////////
I believe there should be some way to go directly from a ucar.nc2.Variable to a primitive byte array in 5 seconds or less. 


Thanks,


NOAA International Division - FX-Net

-William Ruddick

address@hidden <mailto:address@hidden>

303-497-6757