Re: [netcdf-java] Reading "linearly" through a multi-dimensional array

• To: netcdf-java@xxxxxxxxxxxxxxxx
• Subject: Re: [netcdf-java] Reading "linearly" through a multi-dimensional array
• From: Hanns Holger Rutz <rutz@xxxxxx>
• Date: Thu, 26 Jan 2017 16:58:18 +0100

hi there,

for the record, i managed to implement an algorithm that solves
this (
https://stackoverflow.com/questions/41850946/linearly-reading-a-multi-dimensional-array-obeying-dimensional-sub-sectioning#41870662
shows how to generate the sub-ranges within the overall section to be read )

best, .h.h.


On 25/01/17 12:20, Hanns Holger Rutz wrote:
> hi there,
> 
> I have a scenario where I need to read the entire contents of a
> multi-dimensional section'ed variable piecewise linearly.
> 
> for example, say the variable has shape [a][b][c] and I have section'ed
> it as [s1][s2][s3]. say data type is double. now i need to read the
> stream of elements, the total size of which is s1.size * s2.size *
> s3.size in chunks, for example of chunk size x.
> 
> the API for variable doesn't allow me to specify "flat" linear indices,
> so I need to calculate intermediate sub-sections, I guess. this looks
> very complicated because the chunk size x might not be a simple multiple
> of s3.size, s2.size*s3.size, etc.
> 
> So I can only think of two approaches: read "too" much data and then
> throw away some. Read multiple times; perhaps this problem can be
> formulated in maximally three read calls?
> 
> Has anyone solved this somehow? Or is there a trick in the API that I
> haven't seen, to get a linear read command that preserves the offsets
> and strides of sections?
> 
> thanks, .h.h.
> 
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