I would like to add data in chunks(2d arrays) to the dataset with unlimited size in Fortran.
Is there any way where I can simply open and extend the existing dataset without rewriting the whole data?
As I understood I have to open the file in RDWR mode: CALL h5fopen_f(filename, H5F_ACC_RDWR_F, file, hdferr)
Extend dimensions, where dims are old dimensions and extdims = (/dims(1), dims(2)+5/) - add 5 more lines CALL h5dset_extent_f(dset, extdims, hdferr)
Then, my question is how to write additional data without rewriting the old data? Can I somehow specify the initial index for writing? CALL h5dwrite_f(dset, H5T_NATIVE_INTEGER, wdata2, extdims, hdferr)
Please find below an example in Fortran using HDFql (not sure how this is done with other APIs) that creates an HDF5 file named test.h5 and, within it, creates a dataset named dset. This dataset is extendible (on its first dimension) and is populated with data coming from an hypothetical function named acquire. The populating is done through an hyperslab selection so that previous written data is not overwritten.
PROGRAM Example
USE HDFql
CHARACTER :: variable_number
INTEGER, DIMENSION(1024) :: values
INTEGER :: state
state = hdfql_execute("CREATE AND USE FILE test.h5")
state = hdfql_execute("CREATE DATASET dset AS INT(0 TO UNLIMITED, 1024)")
WRITE(variable_number, "(I0)") hdfql_variable_register(values)
DO WHILE(acquire(values)) ! call hypothetical function that acquires data
state = hdfql_execute("ALTER DIMENSION dset TO +1")
state = hdfql_execute("INSERT INTO dset(-1:::) VALUES FROM MEMORY " // variable_number)
END DO
state = hdfql_variable_unregister(values)
state = hdfql_execute("CLOSE FILE")
END PROGRAM
