Re: skip, stride reading...

Tom Rink wrote:

> Hi,
>
> How can skip or stride reading be done in the Java
> implementation of NetCDF? Is there an equivalent
> operation?
>
> Tom Rink

Hi Tom:

I seem to have overlooked implementing a stride-based read, probably 
because the original (version 1) library doesnt have one. I will add 
this to the to-do list.

Meanwhile, you can get a strided subset of an Array, which will be 
equivilent except that you probably have to read more than you need:

Suppose you have a 3D Array, and you want to access it with stride 2, 1, 
and 3 in the three dimensions. The following will give you a logical 
view of the data with those strides, using the same backing data as the 
original:

Array data = var.read();
int[] shape = data.getShape();
Array dataS;
Range[] ranges = new Range[] { new Range(0,shape[0]-1, 2), null, new 
Range(0,shape[2]-1, 3) };

try {
dataS = data.section( ranges);
} catch (InvalidRangeException e) {
System.out.println("testStride failed == "+ e);
}

Note that the null second Range means “use all with stride one”. You can 
make a copy to get just the subset you want, so that the original data 
memory can be freed up:

dataS = dataS.copy(); // now is a separate data array