Re: requirements for anonymous dimensions (and question for John)

> ed@xxxxxxxxxxxxxxxx wrote:
> 
> >>From our requirements on anonymous dimensions:
> >
> >* Dimensions do not always require a name. 
> >
> >By this do we mearly mean that I can accept a dimension with a zero
> >length name, and that's it?
> >
> >Otherwise it acts exactly like a regular dimension?
> >
> >If so, this will be an easy one!
> >
> >John, was there something else you had in mind for this that I am missing?
> >Ed
> >  
> >
> anonymous dimensions are local to the variable, as opposed to globally 
> scoped dimensions which can be shared across variables. anonymous 
> dimensions can be nameless, but it would be ok if they had a name if 
> someone had an idea why that would be useful.
    Hmm, why not just call them "private dimensions" then?

        Quincey
>From owner-netcdf-hdf@xxxxxxxxxxxxxxxx 19 2003 Dec -0700 12:51:54 
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Date: 19 Dec 2003 12:51:54 -0700
From: Ed Hartnett <ed@xxxxxxxxxxxxxxxx>
In-Reply-To: <20031219132116.E29507@xxxxxxxxxxxxxxxxxxxxx>
To: netcdf-hdf@xxxxxxxxxxxxxxxx
Subject: Re: NCSA access to the netcdf4 prototype?
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"Robert E. McGrath" <mcgrath@xxxxxxxxxxxxx> writes:

> Russ & Ed,
> 
> Several of us here at NCSA would like to look at the prototype.  We
> don't know
> how to get to it.
> 
> How do you guys want to handle this?  Do you want to set up remote
> access to your
> CVS? Or what?
> 

Howdy!

Russ and I just made some decisions about the way we're going to
distribute the software. Give me a couple of days to implement those
decisions, then you should just be able to get a tarball and
configure and install in the usual fashion.

We had intended to distribute the netcdf-3 and netcdf-4 libraries
seperately, but now we've realized that we better package them
together...

Ed

>From owner-netcdf-hdf@xxxxxxxxxxxxxxxx 24 2003 Dec -0700 05:18:33 
Message-ID: <wrxn09ijtnq.fsf@xxxxxxxxxxxxxxxxxxxxxxx>
Date: 24 Dec 2003 05:18:33 -0700
From: Ed Hartnett <ed@xxxxxxxxxxxxxxxx>
To: netcdf-hdf@xxxxxxxxxxxxxxxx
Subject: some performance benchmarks for netcdf-4
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Howdy all!

Russ suggested to me yesterday that I post these timing results. In
the tests below I write, and then read, 4 files. The first is in HDF5,
with no netCDF stuff at all. (Writing BE on a LE system, because
that's what netcdf does). The second file is pure netcdf-3, with no
netcdf-4 code involved. The third uses the netcdf-4 library to write a
file in netcdf classic format. Finally, the last file is created with
netcdf-4, with HDF5 as a storage layer. This is faster because it is
writing LE on a LE system (i.e. using HDF "native" format).

The CPU time is the combined total of time spent by the CPU on
user/library code, and the User time is wall clock time.

Russ would like to include some of these results in an AMS paper, but
I think we all need to give a thought to what we are measuring first.

About to write pure HDF5 file, one dataset, record by record: x 2000 y 300 z 
500...
avg CPU time =   15.17 secs.
avg User Time = 43 secs.

About to write pure netcdf-3 file, record by record...
avg CPU time =   17.15 secs.
avg User Time = 45 secs.

About to write netcdf-3 file thru netcdf-4, record by record...
avg CPU time =   17.26 secs.
avg User Time = 45 secs.

About to write netcdf-4 (i.e. HDF5) file, record by record...
avg CPU time =   15.87 secs.
avg User Time = 36 secs.

About to read pure HDF5 file...
avg CPU time =   13.70 secs.
avg User Time = 34 secs.

About to read pure netcdf-3 file...
avg CPU time =    9.18 secs.
avg User Time = 29 secs.

About to read netcdf-3 file, created with netcdf-4...
avg CPU time =   11.64 secs.
avg User Time = 20 secs.

About to read netcdf-4 (i.e. HDF5) file...
avg CPU time =   12.49 secs.
avg User Time = 20 secs.

>From owner-netcdf-hdf@xxxxxxxxxxxxxxxx 24 2003 Dec -0700 05:26:54 
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Date: 24 Dec 2003 05:26:54 -0700
From: Ed Hartnett <ed@xxxxxxxxxxxxxxxx>
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To: netcdf-hdf@xxxxxxxxxxxxxxxx
Subject: Re: some performance benchmarks for netcdf-4
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I forgot to mention that the times I posted are the average times of
each operation, averaged over 30 cycles of writing and reading the
files.

Ed