Hi Rafael,
Thank you for your reply!
I am using Visual Studio (C#) and HDF5 P/Invoke. While the syntax is a bit
different from C/C++, the HDF5 functions should do the same.
I am indeed setting the type argument to the native double type. I paste my
(simplified yet still quite lengthy) code below.
It is the status in the try block in the very end that returns -1. This
works fine if I pass the double[] valuesOneDim to H5D.write instead of the
byte[] byteData.
// Create a H5F file and H5G group (not included)
hid_t groupId = ...
// Create dataspace and dataset:
int nCols = 30;
int nRows = 5;
htri_t rank = 2;
ulong[] dims = new ulong[2] { 0, nCols };
ulong?[] maxDims = new ulong[2] { H5S.UNLIMITED, nCols };
string name = "TestDataset";
hid_t dataspaceId = H5S.create_simple(rank, dims, maxDims);
hid_t pList = H5P.create(H5P.DATASET_CREATE);
H5P.set_layout(pList, H5D.layout_t.CHUNKED);
H5P.set_chunk(pList, rank, new ulong[] { 1, (ulong)maxDims[1] });
hid_t datasetId = H5D.create(groupId, name, H5T.NATIVE_DOUBLE, dataspaceId,
H5P.DEFAULT, pList, H5P.DEFAULT);
H5P.close(pList);
// Generate a 2D (5x30) random double array and converting it to a 1D byte
array.
Random random = new Random();
double[,] values = new double[nCols, nRows];
double[] valuesOneDim = new double[nCols * nRows];
int nBytes = 8;
byte[] byteData = new byte[nCols * nRows * nBytes];
for (int i = 0; i < nCols; i++)
{
for (int j = 0; j < nRows; j++)
{
values[i, j] = random.NextDouble();
valuesOneDim[i + nCols * j] = values[i, j];
byte[] thisByteValue = BitConverter.GetBytes(values[i, j]);
for (int k = 0; k < nBytes; k++)
{
byteData[k + nBytes * (i + nCols * j)] = thisByteValue[k];
}
}
}
// Write byte array to dataset
htri_t status = -1;
int arrayCols = (htri_t)(dims[1]);
int existingRows = (htri_t)(dims[0]);
int appendRows = data.GetLength(0) / Marshal.SizeOf(typeof(T)) /
arrayCols; // This number is 5, just like nRows.
htri_t nBytes = Marshal.SizeOf(typeof(T)) * arrayCols * appendRows; // =
5*30*8=1200
ulong[] appendDims = new ulong[] { (ulong)appendRows, (ulong)arrayCols };
// [5, 30]
hid_t memSpaceId = H5S.create_simple(2, appendDims, null);
ulong[] start = new ulong[2] { (ulong)existingRows, 0 }; // [0, 0]
ulong[] count = new ulong[2] { (ulong)appendRows, (ulong)arrayCols }; //
[5, 30]
dataspaceId = H5D.get_space(datasetId);
H5S.select_hyperslab(dataspaceId, H5S.seloper_t.SET, start, null, count,
null);
GCHandle handle = default(GCHandle);
try
{
handle = GCHandle.Alloc(byteData, GCHandleType.Pinned);
using (SafeArrayBuffer buffer = new
SafeArrayBuffer(Marshal.AllocHGlobal(nBytes)))
{
Marshal.Copy(byteData, 0, buffer.DangerousGetHandle(), nBytes);
status = H5D.write(datasetId, H5T.NATIVE_DOUBLE, memSpaceId,
dataspaceId, H5P.DEFAULT, buffer.DangerousGetHandle());
}
}
finally
{
handle.Free();
}
// Close dataspaces, datasets, types, etc (not included).
...
> Hi Johan,
>
> The second argument to H5Dwrite function (referring to C API, not C++)
> sets the type of single element which is expected in data buffer. If you
> set this to H5T_NATIVE_DOUBLE everything should be fine and data should
> be properly written since data buffer is just a pointer (void*).
>
> https://support.hdfgroup.org/HDF5/doc/RM/RM_H5D.html#Dataset-Write
>
> Usually -1 status means that you messed something with memory space and
> file space (3rd and 4th argument of H5Dwrite) and/or dataset dimensions.
> Please send some of your code examples (including how dataset is
> created) for further investigation...
>
> Regards,
> Rafal
>
>
> W dniu 2017-10-18 o?14:21, Johan Lindberg pisze:
> > Hi,
> >
> > Is there a way to write raw binary byte array data to an existing
> > dataset of a different type? E.g., if I have a byte array that
> > represents an array of doubles (the byte array thus has 8 times as many
> > elements as the double array, where each set of 8 bytes represents a
> > double), can I somehow write that data to a double dataset in an HDF5
> > file? Trying this the na?ve way with HDF.write just returns a -1 status.
> >
> > The reason why I don't just convert it to a double array before writing
> > is that I have an instrument which returns all its data in byte arrays,
> > no matter the type, and then I'd have to write a converter for each of
> > the 10 different types it output in.
> >
> > Thank you,
> > Johan Lindberg
> >
> > --
> > Dr. Johan E. Lindberg
> >
> >
> > _______________________________________________
> > Hdf-forum is for HDF software users discussion.
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> >
>
>
>
>
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>
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>
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>
--
Dr. Johan E. Lindberg
Mobile phone: +46 (0)76-209 14 13
e-mail: jolin...@gmail.com
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