Hey, that’s pretty cool! Thanks for sharing that.

Nope, I haven’t tried that.

Alas, I don’t think I can use it either because I need finer grained control 
over properties controlling dataset creation and transfer and type conversion.

If an hid_t for creation props and another hid_t for transfer props were 
provided as optional args to these routines, that could potentially make them 
more generally useful t cases like mine.

The H5CPP interface looks really useful for common/simple cases, but I would 
rather that templatization of HDF5 compile-time types NOT to be too closely 
coupled with other aspects of data set creation and I/O (or container classes).

Thanks again for sharing though.

Mark


"Hdf-forum on behalf of Steven Varga" wrote:

hello,

did you try H5CPP<http://h5cpp.ca/>? You  can find the implemented 
functionality in the code base or freely use the C++14 template library for 
vectors, and armadillo matrices.  The github page is 
here<https://github.com/steven-varga/h5cpp>

At this stage the profiled templates can handle armadillo vectors, matrices and 
cubes, as well stl vectors and structs.

best,
steven

On Mon, Feb 5, 2018 at 6:03 PM, Miller, Mark C. 
<[email protected]<mailto:[email protected]>> wrote:
Hi All,

I am wondering if anyone else in C++ coding of HDF5 has run into the following 
problem…

I have a templatized function that writes an HDF5 dataset…

template <class T> static void WriteVecToHDF5(hid_t fid, char const *name, 
std::vector<T> const &vec, int d2size)
{
    hsize_t siz2d[2] = {(hsize_t) vec.size() / d2size, d2size};
    hid_t spid = H5Screate_simple(d2size>1?2:1, siz2d, 0);
    hid_t dsid = H5Dcreate(fid, name, HDF5Type<T>().Type(), spid, H5P_DEFAULT, 
H5P_DEFAULT, H5P_DEFAULT);
    H5Dwrite(dsid, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, &vec[0]);
    H5Dclose(dsid);
    H5Sclose(spid);
}

I would like the template instantiation to then return the correct 
H5T_NATIVE_XXX type so WriteVecToHDF5<int>(…) produces a call to H5Dcreae, 
there in bold red with H5T_NATIVE_INT, etc.

There does not appear to be any support in the HDF5 implementation for this. Am 
I missing something?

Below is what I did (for int, float and double but can easily be expanded to 
cover all primitive types) and am wondering if others find this useful enough 
(or something like it) that it ought to be included in HDF5 C++ interface?


// base class
template <class T> class HDF5TypeBase {
  public:
             HDF5TypeBase() {} ;
    virtual ~HDF5TypeBase() {};
};


// base class for type-specific template specializations to follow
template <class T> class HDF5Type : public HDF5TypeBase<T> {
  public:
    HDF5Type() : HDF5TypeBase<T>() {};
    virtual ~HDF5Type() {};
    virtual hid_t Type() const { return H5T_NATIVE_HERR; };
};

// int, H5T_NATIVE_INT specialization
template <> class HDF5Type<int> : public HDF5TypeBase<int> {
  public:
    HDF5Type() : HDF5TypeBase<int>() {};
    virtual ~HDF5Type() {};
    virtual hid_t Type() const { return H5T_NATIVE_INT; };
};

// float, H5T_NATIVE_FLOAT specialization
template <> class HDF5Type<float> : public HDF5TypeBase<float> {
  public:
    HDF5Type() : HDF5TypeBase<float>() {};
    virtual ~HDF5Type() {};
    virtual hid_t Type() const { return H5T_NATIVE_FLOAT; };
};

// double, H5T_NATIVE_DOUBLE specialization
template <> class HDF5Type<double> : public HDF5TypeBase<double> {
  public:
    HDF5Type() : HDF5TypeBase<double>() {};
    virtual ~HDF5Type() {};
    virtual hid_t Type() const { return H5T_NATIVE_DOUBLE; };
};

This permits in the HDF5Type<T>().Type(), bold red, in the snipit above, to 
actually work

--
Mark C. Miller, LLNL

"In the end, we will remember not the words of
our enemies but the silence of our friends" - MLK

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