There is no other way of reading C arrays into Fortran ordering than
ordering conversion, but it can be implemented optimally as an in-place
transpose (once already in memory) on the reader side. This costs time,
not storage. I so much hoped this would be a feature of xdmf2 for
example, it is one in my own home grown hdf5 Paraview reader. --DS
John R. Cary wrote:
Dominik Szczerba wrote:
You will need SetArray method from the concrete implementation of
vtkDataArray. I could not quickly find in the source code any hints
about the underlying storage ordering, but it is trivial to find out
experimentally. Just post the results please. If it is the same as
yours no copying is needed.
Well, I was unable to figure out how to get hdf5 to read the data
in by Fortran order, so I wrote the snippet below. Sending by
request.
This is probably slow, so better solutions always welcome.
John Cary
// The index tuple is initially zero
size_t* indices = new size_t[rank];
for(size_t k=0; k<rank; ++k) indices[k] = 0;
// Step through by global C index
for(size_t k = 0; k<len; ++k) {
// Accumulate the Fortran index
size_t indx = indices[rank-1];
for(size_t j = 2; j<=rank; ++j) indx = indx*dims[rank-j] +
indices[rank-j];
// Set the value in the VTK array at the Fortran index to the
// value in the C array at the C index
if (H5Tequal(type, H5T_NATIVE_DOUBLE)) rv->SetTuple(indx,
&((double*) data)[k]);
if (H5Tequal(type, H5T_NATIVE_FLOAT)) rv->SetTuple(indx,
&((float*) data)[k]);
// Update the index tuple
size_t j = rank;
do {
--j;
++indices[j];
if (indices[j] == dims[j]) indices[j] = 0;
else break;
} while (j != 0);
}
John R. Cary wrote:
I have arrays written out from C into HDF5 using the HDF5 C
API, and so in the file the arrays are in C ordering. I now
need to read them into VTK. AFAICT, VTK is Fortran ordering,
even though it is written in C++. So that means I need to
reverse the ordering. Of course, I can write a loop to do
this, but is there some standard way that VTK folks do this?
I don't want to reinvent the wheel.
Sorry for what is likely an elementary question, but I could
not find it on the FAQ or after googling quite a bit.
Thanks so much......John Cary
--
Dominik Szczerba, Ph.D.
Foundation for Research
on Information Technologies in Society
http://www.itis.ethz.ch
_______________________________________________
ParaView mailing list
[email protected]
http://www.paraview.org/mailman/listinfo/paraview
