Hi all,
I'm trying to do what I thought was a fairly straightforward
field.evaluate(blah) call, and ended up with some NullPointerExceptions.
It's a tool under development, so I *might* be giving bad samples or
something like that, but I'll post various bits of code and stack trace,
and you can make up your own minds. I looked at the VisAD source to try
to see what was going on. The datestamp on my visad.jar is July 14th,
and the source I'm working from is out of the visad_src.jar with the
same timestamp. I included a lot of code / traces, so hopefully what you
need is here. Let me know if I've made a dumb error....
My code is :
.....
double[][] timeSet =
animationControl.getSet().getDoubles(false);
Real timeSample = new Real(RealType.Time,
timeSet[0][animationControl.getCurrent()]);
FieldImpl distanceField =
(FieldImpl)field.evaluate(timeSample);
System.out.println(distanceField.getType().toString());
RealTuple domainSample = new
RealTuple(LEVEL_DISTANCE_TYPE, new double[] { dDistance, dHeight });
System.out.println(domainSample.toString());
Data intensityData = distanceField.evaluate(domainSample);
RealTuple intensityTuple = (RealTuple) intensityData;
double[] intensityValues = intensityTuple.getValues();
.....
with the error occurring on the line that reads
Data intensityData = distanceField.evaluate(domainSample);
The mathType of the FieldImpl is :
((LevelXS, VerticalDistanceXS) -> XSGASPMIX)
The RealType I'm trying to evaluate has the samples :
(224.13154940119756, 205.24017467248817)
Both those numbers are valid numbers to ask for, for either level _or_
distance, so it's not a silly specified-the-samples-wrong problem.
The stack trace is :
java.lang.NullPointerException
at
visad.Gridded2DDoubleSet.valueToInterp(Gridded2DDoubleSet.java:256)
at visad.FieldImpl.resample(FieldImpl.java:2762)
at visad.FunctionImpl.evaluate(FunctionImpl.java:169)
at visad.FunctionImpl.evaluate(FunctionImpl.java:146)
at
au.gov.bom.aifs.dv.xsection.CrossSectionDialog.displayData(CrossSectionDialog.java:787)
at
au.gov.bom.aifs.dv.xsection.CrossSectionDialog.access$900(CrossSectionDialog.java:57)
at
au.gov.bom.aifs.dv.xsection.CrossSectionDialog$MouseMovedListener.mouseMoved(CrossSectionDialog.java:811)
at
java.awt.AWTEventMulticaster.mouseMoved(AWTEventMulticaster.java:271)
at java.awt.Component.processMouseMotionEvent(Component.java:5145)
at java.awt.Component.processEvent(Component.java:4901)
at java.awt.Component.dispatchEventImpl(Component.java:3615)
at java.awt.Component.dispatchEvent(Component.java:3477)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)
Gridded2DDoubleSet.valueToInterp reads :
/** for each of an array of values in R^DomainDimension, compute an array
of 1-D indices and an array of weights, to be used for interpolation;
indices[i] and weights[i] are null if i-th value is outside grid
(i.e., if no interpolation is possible) */
public void valueToInterp(float[][] value, int[][] indices,
float[][] weights) throws VisADException
{
int len = weights.length;
double[][] w = new double[len][];
for (int i=0; i<len; i++) w[i] = new double[weights[i].length];
doubleToInterp(Set.floatToDouble(value), indices, w);
for (int i=0; i<len; i++) {
System.arraycopy(w[i], 0, weights[i], 0, w.length);
}
}
With the problematic line being :
for (int i=0; i<len; i++) w[i] = new double[weights[i].length];
Looking at at visad.FieldImpl.resample(FieldImpl.java:2762), which is
the calling line shows :
int[][] indices = new int[length][];
float[][] coefs = new float[length][];
((GriddedSet) DomainSet).valueToInterp(vals, indices, coefs); <--
this is the calling line
So the weights[][] array in interp is this coefs array. The line " for
(int i=0; i<len; i++) w[i] = new double[weights[i].length];" doesn't
seem like it will ever work, because it's always a new double[length][],
i.e. null for all i.
Cheers,
-Tennessee
