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[netCDF #NNS-961385]: nf90_put_var slows down erratically

David,

We're trying to learn enough about chunking to improve the
documentation in that respect and give some good guidance, but as
you've discovered, we aren't there yet.

Your definition for chunksize is exactly right for the Fortran90
interface,

  chunksizes= (/ 32,64,64,1 /)

but in looking at this we just discovered that the F90 API doesn't
reverse the chunksizes when calling the corresponding C function.  Ed
just fixed that, and the fix will be in the snapshot release created
tonight.  But until then, you could test that this really is the
problem by reversing your chunksizes to use the C order, and let us
know if things work with that change:

  chunksizes= (/ 1,64,64,32 /)

If that works, you'll have to reverse them again to run against the
bug-fixed release after tonight.

I don't know what the non-helpful "HDF error" means, other than that
we are not translating HDF5 errors into helpful error messages at the
netCDF layer.  It seems like the chunksizes you gave, while
non-optimal if the order is reversed, should still have worked ...

--Russ

Russ Rew                                         UCAR Unidata Program
address@hidden                     http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: NNS-961385
Department: Support netCDF
Priority: Normal
Status: Closed