[ncl-install] NCL install with NetCDF-4 undeclared variable NC_NETCDF4

[Mary Haley]

On Tue, 17 Feb 2009, Marcin Sliwowski wrote:

> Mary,
>
> Thank you very much for your explanation. I am now content with this.
>
> One last thing I need to ask, even though I say no to the classic
> netCDF-4 support question in NCL's configure, will NCL still be able to
> handle other  prior netCDF formatted input files such as the ones
> without compression?

Yes, you will have full access to NetCDF-3 capabilities, even
if you say "no" to classic NetCDF-4 support.

>
> In case you are curious I am installing NCL and NCARG for use with a
> Weather Research Forcasting (WRF) model, and they state that they do not
> support netCDF-4 enhanced features, and instead to use netcdf-3 and
> netCDF-3.6 for large file support. They told me that if you install
> netcdf4 without invoking HDF5 and netCDF-4 capabilities, it should be ok
> to use netcdf4. I believe that this is what I have done by disabling
> netcdf4 along the way, I just hope the NCL I end up with still has some
> netCDF support in it.

What the WRF page says is absolutely correct, so you should be fine
using NetCDF version 4.0, but then disabling the NetCDF-4 support
(which is the default). Very confusing!

--Mary

> Thank You,
> Marcin
>
> Mary Haley wrote:
>>> Mary,
>>>
>>> I am still confused on this topic.
>>>
>>> The netcdf site states the following:
>>>
>>> the netCDF-4.x releases will only build with the netCDF-4 enhanced
>>> features if "--enable-netcdf-4" is provided as a configure option. By
>>> default the distribution will build the classic netCDF-3 library. We
>>> believe that most users will not need the enhanced netCDF-4 features at
>>> this time.
>>>
>>> So when I read the above I actually did not have to specify
>>> --disable-netcdf-4 when configuring my netCDF install but I did it just
>>> in case.
>>
>> That's correct. The NetCDF-4 features are not built by default.
>>
>>> expected the end product to be a classic netCDF-4 without the
>>> new enhanced features. Then when I am configuring NCL and it asks do I
>>> want classic netCDF-4 support I say yes.
>>>
>>> Is there a mislabeling of what classic means between NCL and netCDF-4?
>>>
>>> I thought that classic NetCDF-4 is basically the previous netCDF-3
>>> format support within netCDF-4. The new enhanced netCDF-4 feature is the
>>> use of HDF-5 instead of HDF-4 and is enabled by the config flag
>>> --enable-netcdf-4
>>>
>>
>> Yes, this is half correct, but classic NetCDF-4 and classic NetCDF-3
>> are *not* the same thing.
>>
>> Classic NetCDF-4 is using HDF 5 under the hood, and has
>> compression capabilities.  What this means is that the NetCDF-3
>> interface is still being used to create the files, but under the hood,
>> an HDF-5 file is being written *and* you have access to compression.
>>
>> If you don't need compression capabilities, then my recommendation
>> is to build NetCDF with the --disable-netcdf-4 option, and then
>> when you run NCL's "./Configure", answer "no" to the "do you need
>> classic NetCDF 4 support" question.
>>
>> --Mary
>>
>>> I have read the NCL installation guide front and back focusing on the
>>> NetCDF section and there does seem to be some confusion regarding what
>>> classic means:
>>>
>>> The guide states without classic netCDF-4 support configure the
>>> following way:
>>>
>>> ./configure --disable-f90 --prefix=/usr/local
>>>
>>> With "classic" netCDF-4 support it instructs to get HDF-5 and set the
>>> configure flag enable-netcdf-4, but this is in contrast to what the
>>> netCDF site states. It seems that NCL is misusing the term classic, to
>>> mean the brand new and enhanced netCDF-4.
>>>
>>> Please correct me if I am wrong.
>>>
>>> Thanks,
>>> Marcin
>>>
>>>
>>> Mary Haley wrote:
>>>> Hi Marcin,
>>>>
>>>> If you want classic NetCDF 4 support, then you will need to build
>>>> NetCDF 4.x with --enable-netcdf set, and make sure --disable-netcdf-4
>>>> is not set.
>>>> Everything else you're doing is correct.
>>>>
>>>> You may also want to look at #6 at:
>>>>
>>>> http://www.ncl.ucar.edu/Download/build_from_src.shtml#Troubleshooting
>>>>
>>>> With the newer versions of HDF, the "hdf/netcdf.h" include file
>>>> doesn't get installed, so you need to remove this reference from the
>>>> NCL code.
>>>>
>>>> --Mary
>>>>
>>>> On Mon, 16 Feb 2009 15:42:37 -0500
>>>>  Marcin Sliwowski <ms275 at duke.edu> wrote:
>>>>> Hello Everyone,
>>>>>
>>>>> I installed netCDF-4 and used the following config flags:
>>>>>
>>>>> --prefix=/usr/local/netcdf-4.0-pgi --disable-shared
>>>>> --enable-large-file-tests --enable-docs-install --disable-netcdf-4
>>>>>
>>>>> I installed hdf4.2r4 and used the following config flags:
>>>>>
>>>>> --prefix=/usr/local/hdf4.2r4-pgi/ --disable-netcdf
>>>>> --with-jpeg=/usr/local/jpeg-6b-pgi
>>>>>
>>>>>
>>>>> My problem is on compiling NCL v5.0.0, Two problems encountered and
>>>>> solved via troubleshooting guide, one last error remains.
>>>>>
>>>>> During the NCL configure I say yes to include netCDF-4 support into
>>>>> NCL
>>>>> because according to the way I understand it I am only asking for the
>>>>> "classic" NetCDF support not the new extended netCDF, which is why
>>>>> I set
>>>>> the flag --disable-netcdf-4 on the config for netCDF-4
>>>>>
>>>>> Error 1: PGC-F-0206-Can't find include file hdf/netcdf.h (NclHDF.c:
>>>>> 26)
>>>>> Solved by commenting out: #include <hdf/netcdf.h> in NclHDF.c and
>>>>> NclHDFEOS.c as suggested by troubleshooting guide
>>>>>
>>>>> Error 2: PGC-S-0039-Use of undeclared variable MAX_NC_NAME (NclHDF.c:
>>>>> 313)
>>>>> Solved by inserting the #defines as indicated in the troubleshooting
>>>>> guide
>>>>>
>>>>> Error 3: PGC-S-0039-Use of undeclared variable NC_NETCDF4
>>>>> (NclNetCdf.c: 744)
>>>>> PGC-S-0039-Use of undeclared variable NC_CLASSIC_MODEL (NclNetCdf.c:
>>>>> 744)
>>>>>
>>>>> This error does not occur when I answer "no" to the include netCDF-4
>>>>> support into NCL, but I want the classic NetCDF-4 support in NCL.
>>>>>
>>>>> Does anyone have any guidance or advice to get by this error?
>>>>>
>>>>> Thank You,
>>>>> Marcin
>>>>>
>>>>> --
>>>>> Marcin Sliwowski
>>>>> Systems Programmer
>>>>> Duke University - Pratt School of Engineering
>>>>> 919-660-8450
>>>>>
>>>>> _______________________________________________
>>>>> ncl-install mailing list
>>>>> List instructions, subscriber options, unsubscribe:
>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-install
>>>>
>>>
>>>
>>> --
>>> Marcin Sliwowski
>>> Systems Programmer
>>> Duke University - Pratt School of Engineering
>>> 919-660-8450
>>>
>>>
>
>
> -- 
> Marcin Sliwowski
> Systems Programmer
> Duke University - Pratt School of Engineering
> 919-660-8450
>
>