I created a little test program (at the end of this email), and observed
the following: If I do _not_ do a System.gc() just before printing out
the memory usage info, then the values support your observation (17.3MB
versus 12.3). However, after nulling out the data array and doing a
garbage collection, the values become 5.3MB and 8.3MB, respectively.
Therefore, your observation might not be completely representative of
how much memory is actually required. As far as I can tell, since your
range set has 255 elements, the data actually stored in the FlatField
should be in bytes.
Hope that helps...
tom
Here's the test program:
import java.*;
import visad.*;
import java.lang.*;
public class olver {
public static void main(String[] a) {
try {
RealType rt1 = new RealType("xc");
RealType rt2 = new RealType("yc");
RealType rt3 = new RealType("rc");
RealTupleType dt = new RealTupleType(rt1,rt2);
FunctionType ft = new FunctionType(dt, rt3);
Integer2DSet ds = new Integer2DSet(1000,1000);
Integer1DSet[] rs = { new Integer1DSet(rt3, 255)};
//FlatField ff = new FlatField(ft, ds, null, null, rs, null);
FlatField ff = new FlatField(ft, ds, null, null, null, null);
float[][] data = new float[1][1000 * 1000];
int z=0;
for (int i=0; i<1000; i++) {
for (int j=0; j<1000; j++) {
data[0][z] = i+j;
z++;
}
}
ff.setSamples(data);
data = null;
System.gc();
double totalMemory = (double) Runtime.getRuntime ().totalMemory ();
double freeMemory = (double) Runtime.getRuntime ().freeMemory ();
double usedMemory = (totalMemory-freeMemory);
int percent = (int)(100.0*(usedMemory/totalMemory));
totalMemory = totalMemory/1000000.0;
usedMemory = usedMemory/1000000.0;
System.out.println("#### total, used, percent="+totalMemory+"
+usedMemory+" "+percent);
} catch (Exception e) {e.printStackTrace(); }
}
}
OLVER OLFREY HERNANDEZ NAVARRO wrote:
Hi all.
I'm working with Satellite Images, and I'm using visad to visualizate
them. I need that visad use less memory, then I try to construct the
FlatField in this way:
new FlatField( func_domain_range, domain_set,null,null,new Integer1DSet[]
{new Integer1DSet(varRaster,255)},null);
but it spend more memory that in this way:
new FlatField( func_domain_range, domain_set,null,null,null,null);
Why the first one use more memory?
Thank's
--
Olver Hernández
Facultad de Minas
Universidad Nacional de Colombia
Sede Medellín
--
Tom Whittaker (tomw@xxxxxxxxxxxxx)
University of Wisconsin-Madison
Space Science and Engineering Center
Cooperative Institute for Meteorological Satellite Studies
Phone/VoiceMail: 608.262.2759
