I like the idea of a function handle, however I would also like the
ability to
append to a function handle, for e.g. restarted, adaptive or
mesh-altering
simulations. This can easily be done by creating a new group with
metadata when
a function handle is created in append mode. There is no need for
hashing.
Using internal links to metadata when rewriting functions would also
allow us
to use the existing code for reading back functions.
-Øyvind
15. okt. 2013 13:13 skrev "Chris Richardson" <[email protected]>
følgende:
On 15/10/2013 08:17, Øyvind Evju wrote:
2013/10/12 Chris Richardson <[email protected]>
It has been suggested to enhance the HDF5File interface.
I am collecting ideas and comments by the mailing list.
Please
reply if you have any opinions about this
at all.
HDF5 files are like filesystems, and can contain groups
(like
directories) and datasets (like files).
Each group or dataset can also have attributes, which may
be
string, double, or vector<double> for example.
Currently, HDF5File in dolfin allows the following:
read and write of Vector, Function, MeshFunction, Mesh and
MeshValueCollection objects,
via simple write(object, "dataset_name") or read(object,
"dataset_name") methods, see HDF5File.h
Complex objects, such as Functions are saved as HDF5
groups,
containing datasets for e.g. dofmap, vector etc.
Proposal
--------
Allow time-series of any of the usual objects listed
above. This
could also be used to reorganise
TimeSeriesHDF5 (in dolfin/adaptivity)
Implementation
--------------
Rather than just writing once, a Function or Vector may be
written
many times, perhaps with timestamp
information.
u = Function(Q)
hdf = HDF5File("example.h5", "w")
# Suggestions for better object names are welcome...
hdf_u = HDF5FunctionHandle("/my_function", u)
hdf_u.write(0.0)
...
# later time
hdf_u.write(1.0)
To read back in:
u = Function(Q)
hdf = HDF5File("example.h5", "r")
hdf_u = HDF5FunctionHandle("/my_function", u)
# read back at time t=0.0
t=0.0
hdf_u.read(t)
# or just read back the next in sequence
hdf_u.read()
I'm curious about the HDF5FunctionHandle. I guess you would
need to
send the hdf5file object on initiation?
Yes, I guess I forgot that...
hdf_u = HDF5FunctionHandle(hdf, "/my_function", u)
The FunctionHandle would contain a shared_ptr reference to the
function, so
future writes would be guaranteed to be OK (using the same
Function, at
least), so no need to hash anything.
I was thinking of just storing the updated vectors in the same
group.
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