How to add 'ChunkSize' in .h5 file?

I would like to resize my dataset (as shown in the attached picture) from 2x20 to 2x3. To achieve this it is necessary to have the ChunkSize to be 2x3. I have been trying to fix this for hours now without any luck. This what I have done so far...

% Ok!, Now let's set the writable attribute of FileName
fileattrib(FileName,'+w');
fid = H5F.open(FileName,'H5F_ACC_RDWR','H5P_DEFAULT');
dset_id = H5D.open(fid,DatasetName);
dcpl = H5D.get_create_plist(dset_id);

chunk_dims = [2 3];

% set it to use the chunked dataset
h5_chunk_dims = fliplr(chunk_dims);
H5P.set_chunk(dcpl,h5_chunk_dims)

% Change size of dataset
H5D.set_extent(dset_id,[3,2]) %[THIS DOES NOT WORK and throw the messag]

=================================
Error using hdf5lib2
The HDF5 library encountered an error and produced the following stack trace information:

    H5D__set_extent    dataset has contiguous storage
    H5Dset_extent      unable to set extend dataset

Error in H5D.set_extent (line 27)
H5ML.hdf5lib2('H5Dset_extent', dset_id, h5_extents);

Answer 1

[Manas Meena]

The error might be because the library cannot find the file/variable that was passed in the “H5P.set_extent” command.

Refer to the below documentation links on how to use the “H5P.set_chunk” and “H5P.set_extent” commands:

https://www.mathworks.com/help/matlab/ref/h5p.set_chunk.html

https://www.mathworks.com/help/matlab/ref/h5d.set_extent.html

You can also refer to the following link to see how to replace a dataset with a smaller dataset in a HDF5 file:

https://www.mathworks.com/support/search.html/answers/415137-how-do-i-replace-a-dataset-in-an-hdf5-file-with-a-smaller-dataset-without-leaving-some-values-of-th.html?fq=asset_type_name:answer%20category:support/introduct1740&page=1