Re: Trying to clip a multi-array

> Date: Mon, 01 Feb 1999 00:30:55 -0800
> From: Scottie Swenson <address@hidden>
> To: address@hidden, address@hidden,
>         address@hidden, address@hidden
> Subject: Re: Trying to clip a multi-array

Hi Scottie,

> I have made significant progress into understanding the ucar classes. In fact 
> I
> have things pretty well under wraps.
> 
> But, I just hit a bug that I am unsure how to properly patch. I am trying to
> such out a clipped array from a larger MultiArray.
> 
> The error message is this:
  ...
> debug: java.lang.NullPointerException
> debug:  at 
> ucar.multiarray.MultiArrayImpl.numberOfElements(MultiArrayImpl.java:58)
> debug:  at ucar.multiarray.MultiArrayProxy.toArray(MultiArrayProxy.java:309)
> debug:  at ucar.multiarray.MultiArrayProxy.toArray(MultiArrayProxy.java:283)
> debug:  at 
> cellworks.footprints.FinniganMS_NETCDF.makeCast(FinniganMS_NETCDF.java:238)
> debug:  at cellworks.moulage.Footprint.run(Footprint.java:964)
> debug:  at java.lang.Thread.run(Thread.java)
>
> The offending chunk of code on my side is this:
> Variable scan_index  = cdf.get("scan_index");
> Variable point_count = cdf.get("point_count");
> Variable mass_values = cdf.get("mass_values");
>
> int[] gi = new int[] {0};
> [...]
> scanOffset = scan_index.getInt(gi);
> scanCount  = point_count.getInt(gi);
>
> // limit the scope of the copy to the range of a the next scan
> ClipMap cm = new ClipMap(0,scanOffset,scanCount);
> 
> // Now get the clipped MultiArray for the masses
> MultiArray mass = new MultiArrayProxy(mass_values, cm);
> 
> double[] masses = (double[])(mass.toArray());

Thanks for reporting this bug.  The appended patch to
src/multiarray/MultiArrayProxy.java should fix the problem.  Please let us
know if it doesn't, or if you find any more bugs.

--Russ

diff -r1.10 MultiArrayProxy.java
309c309
<               final int length = MultiArrayImpl.numberOfElements(shape,
---
>               final int length = MultiArrayImpl.numberOfElements(shp,
312c312
<               final MultiArrayImpl data = new MultiArrayImpl(shape, products,
---
>               final MultiArrayImpl data = new MultiArrayImpl(shp, products,
314c314
<               AbstractAccessor.copyO(this, origin, data, shape);
---
>               AbstractAccessor.copyO(this, origin, data, shp);