Cannot merge sets

I'm getting the following exception while contructing my display with
several fields with different time domains:

visad.VisADException: Cannot merge sets
    at visad.Set.merge1DSets(Set.java:376)
    at visad.DataShadow.setAnimationSampling(DataShadow.java:72)
    at visad.SimpleSet.setAnimationSampling(SimpleSet.java:107)
    at visad.SampledSet.computeRanges(SampledSet.java:208)
    at visad.FieldImpl.computeRanges(FieldImpl.java:2708)
    at visad.DataRenderer.computeRanges(DataRenderer.java:278)
    at visad.DataRenderer.prepareAction(DataRenderer.java:243)
    at visad.DisplayRenderer.prepareAction(DisplayRenderer.java:633)
    at visad.DisplayImpl.doAction(DisplayImpl.java:1383)
    at visad.ActionImpl.run(ActionImpl.java:238)
    at visad.util.ThreadPool$ThreadMinnow.run(ThreadPool.java:95)
visad.VisADError: Action.run: visad.VisADException: Cannot merge sets
    at visad.ActionImpl.run(ActionImpl.java:271)
    at visad.util.ThreadPool$ThreadMinnow.run(ThreadPool.java:95)

It is not consistant (and neither is my data) so I'm wondering if it is
due to the nature of my data. I've looked at the relevant bit of Set
code:

    // find indices of set not covered by this
    int set_length = set.getLength();
    boolean[] set_indices = new boolean[set_length];
    for (int i=0; i<set_length; i++) set_indices[i] = true;
    if (set_length > 1) {
      // set indices for values in this
      int[] test_indices = set.doubleToIndex(values);
      try {
        for (int i=0; i<length; i++) {
          if (test_indices[i] > -1) set_indices[test_indices[i]]
false;
        }
      } catch (ArrayIndexOutOfBoundsException aioobe) {
        throw new VisADException("Cannot merge sets");
      }
    }

but don't quite understand what conditions would lead to this exception.

Let me know if there is something obvious, otherwise I'll try to make a
reproducible case for debugging.

Thanks,
Doug

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| Doug Lindholm, Software Engineer          |  E-mail: lind@xxxxxxxx   |
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