how to append data in hdf5 file.

hdf5write('check_v1.h5','/g1/coordinates',all_data);
hdf5write('check_v1.h5','/g2/coordinates_vel',all_data1);

How do i append the above two datasets?

h5disp('check_v1.h5') %shows the last dataset i write
HDF5 check_v1.h5 
Group '/' 
    Group '/g2' 
        Dataset 'coordinates_vel' 
            Size:  11272228
            MaxSize:  11272228
            Datatype:   H5T_COMPOUND
                Member 'VelocityX':  H5T_IEEE_F64LE (double)
                Member 'VelocityY':  H5T_IEEE_F64LE (double)
                Member 'TargetXCoord':  H5T_IEEE_F64LE (double)
                Member 'TargetYCoord':  H5T_IEEE_F64LE (double)
            ChunkSize:  []
            Filters:  none
            FillValue:  H5T_COMPOUND

Answer 1

[Walter Roberson]

hdf5write('check_v1.h5','/g1/coordinates',all_data);
hdf5write('check_v1.h5','/g2/coordinates_vel',all_data1, 'WriteMode', 'append');