I see the following in the API notes for netcdf::NcGroup::AddVar:
Adds a netCDF variable. The
NcType<http://www.nrel.colostate.edu/projects/irc/public/Documents/Software/netCDF/cpp4/html/classnetcdf_1_1NcType.html>
and
NcDim<http://www.nrel.colostate.edu/projects/irc/public/Documents/Software/netCDF/cpp4/html/classnetcdf_1_1NcDim.html>
objects must be non-null, and be defined in either the current group or a
parent group. An
NcNullType<http://www.nrel.colostate.edu/projects/irc/public/Documents/Software/netCDF/cpp4/html/classnetcdf_1_1NcNullType.html>
exception is thrown if the
NcType<http://www.nrel.colostate.edu/projects/irc/public/Documents/Software/netCDF/cpp4/html/classnetcdf_1_1NcType.html>
object is invalid. An NcNullDim exception is thrown if the
NcDim<http://www.nrel.colostate.edu/projects/irc/public/Documents/Software/netCDF/cpp4/html/classnetcdf_1_1NcDim.html>
object is invalid.
So the NcType must be defined in the current or parent group. How do I define
a type in a group? I cannot see an appropriate function for doing this. Are
types automatically "defined" in a group depending on what type of netCDF file
has been opened (e.g. legacy, 3, 4 etc)? I am opening the file as
netCDF::NcFile::nc4.
Is this the correct way to add variables? In netcdf version 4.1.3, both work.
In version 4.4.0 the first one works, but the second one doesn't.
auto ncFloat = ncFile.getType("float",netCDF::NcGroup::ParentsAndCurrent);
std::vector<float> myFloats = { 1., 2., 3., 4., 5. };
auto ncDim = ncFile.addDim("myFloatsDim", myFloats.size());
auto ncVar = ncFile.addVar("myFloats", ncFloat, {ncDim});
ncVar.putVar(myFloats.data());
auto ncString = ncFile.getType("string",netCDF::NcGroup::ParentsAndCurrent);
std::vector<std::string> myStrings = { "a", "bb", "ccc", "dddd" };
auto ncDim = ncFile.addDim("myStringsDim", myStrings.size());
auto ncVar = ncFile.addVar("myStrings", ncString, {ncDim});
std::vector<const char *> myChars;
for ( auto s : myStrings )
myChars.push_back( s.c_str() );
ncVar.putVar(myChars.data());
I am a bit confused as to why I am seeing this different behaviour with version
4.4.0.
Best regards,
Daniel
________________________________
From: Potter, Daniel (Energy, Newcastle)
Sent: Monday, 5 December 2016 11:02 AM
To: elizabeth.fischer@xxxxxxxxxxxx
Cc: netcdfgroup@xxxxxxxxxxxxxxxx
Subject: Re: [netcdfgroup] NcType problems on Ubuntu 16.04
Hi Elizabeth,
Thank-you for your help and suggestion.
I have tried using NcGroup::getType(), but I still get exceptions when I used
non-netCDF3 types. e.g.:
netCDF::NcFile ncFile("test.nc", netCDF::NcFile::replace,
netCDF::NcFile::nc4);
// works
auto ncFloat = ncFile.getType("float",netCDF::NcGroup::ParentsAndCurrent);
std::cout << "ncFloat.getName() = " << ncFloat.getName() << std::endl;
// throws NcBadType
auto ncString = ncFile.getType("string",netCDF::NcGroup::ParentsAndCurrent);
std::cout << "ncString.getName() = " << ncString.getName() << std::endl;
// throws NcBadType
auto ncUint = ncFile.getType("uint",netCDF::NcGroup::ParentsAndCurrent);
std::cout << "ncUint.getName() = " << ncUint.getName() << std::endl;
Again, this works on Ubuntu 14.04 with netCDF 4.1.3 but not on Ubuntu 16.04
with netCDF 4.4.0. As far as I can tell, this means I cannot make variables of
type string, uint etc?
Best regards,
Daniel
________________________________
From: Elizabeth A. Fischer <elizabeth.fischer@xxxxxxxxxxxx>
Sent: Friday, 2 December 2016 5:07 PM
To: Potter, Daniel (Energy, Newcastle)
Cc: netcdfgroup@xxxxxxxxxxxxxxxx
Subject: Re: [netcdfgroup] NcType problems on Ubuntu 16.04
Daniel,
I believe you're using the "new" (NetCDF4) C++ interface?
It has known problems with NcType, specifically for any types not in the
NetCDF3 data model. I solved them by using strings instead of the symbolic
enums; some of the API functions take strings. If I need a NcType object, I
use the following function to get one:
inline netCDF::NcType nc_type(netCDF::NcVar ncvar, std::string sntype)
{ return ncvar.getParentGroup().getType(sntype,
netCDF::NcGroup::ParentsAndCurrent); }
-- Elizabeth
