New HDF5 VI Library

[whit]

Thanks for the quick response. I will try the select_hyperslab function. BTW I am trying to use the HDF5 interface library by Jason S, with LabVIEW 8.2. This is my first experience with HDF5 and YES the learning curve is steep. I will try to post a new thread, I just realized how old this one was.

gary

[whit]

I am trying to use the hyperslab function but I do not know what to input for Start, Stride, Count, or Block. Could you be a little more specific. Any help is appreciated.

Gary

[DFGray]

A hyperslab is normally defined as a regular array of n-dimensional objects, where n is the number of dimensions of the array.  The array is defined by the start, stride, count, and block sizes.

start - the beginning location in the array
stride - how far to go for the next block
count - how many times to iterate
block - how big each block is

In your case, assuming the z-direction is the frame number, you can specify your hyperslab in numerous ways.  Note that all these numbers are n-dimensional arrays.  The two extremes are:

start = 0,0,frameNumber
stride = 1,1,1
count = 2048,2048,1
block = 1,1,1

This one sets the block and iterations sizes to 1 (rectangular solid is a 1x1x1 cube) and the iterations to 2048 in the x and y to get the whole data.

start = 0,0,frameNumber
stride = 2048,2048,1
count = 1,1,1
block = 2048,2048,1

This one sets the rectangular solid to a 2048x2048x1 plane and one execution.

Both of these should work for you.  I typically would use the top one, but the bottom one may be faster.

[whit]

Thanks for the help, I now get the correct number of 4194304 using the H5Sget_select_npoints. Now how do I actually see the data? HDF is hard!!!!!!!!!!!!! Thanks,

Gary

[DFGray]

Set up a 2D dataspace that is 2048x2048.  Use that as the memory dataspace (you already have the file dataspace using the hyperslab).  Now use the dataset read function to get your data.  You should end up with a 2048x2048 2D array in LabVIEW.  I am not familiar with the API you are using, so be sure you allocate the data (use initialize array) in LabVIEW, since the HDF5 function call needs a pointer.

[whit]

DFGray: Is there any other resources for help on HDF5? I cannot get to the point of reading the data. I am able to hyperslab OK (I think) but I cannot read the data. There seems to be very little examples or additional information, or maybe I do not know where to look. Any help would be appreciated, as I am running into a deadline.

Regards,

gary

[DFGray]

I will reply to your other thread so we quit hijacking this one .

[Kalle Kempe]

Hello

Thank you for an excellent addon to Labview. I have been using it in conjunction with MATLAB with great success so far.

Now however I have run into a problem. I have upgraded Labview to 2011, 64-bit and the HDF5 library is no longer working since h5helper is compiled for 32-bit.

Has anybody recompiled Jason D's sources successfully for any platform? Or are people using other solutions for 64-bit operating systems?

Also, if I use newer versions of the HDF5 libraries (i.e precompiled binary version 1.8.8) from hdfgroup then some calls are broken because the library no longer contains them.

Regards

Kalle

[Alisha_P]

Hi Kalle,

I recommend reposting this as a new thread; I think it will get more attention that way and you may hear more what other developers are doing on 64-bit systems.

As far as I can tell, this isn't something we really support, atleast on Windows 7 64-bit system. Are you using executables/code from our website? or are you using code that Jason D wrote?