Best way to export long double data from C into Matlab

What is the best way to import very large matrices of long double data from C (on Linux) into MATLAB? Please answer so that someone new to both C and MATLAB (that's me) can understand. Thanks.

[Jan]

Are you talking about 80bit values stored in the memory - if so, how are they stored? Or do you mean 80bit values stored in a text or binary file - if so, please explain the format.

[Jeff]

I'm pretty new to the low level details of programming. I see I didn't provide near enough information.

The data is calculated one row at a time by an ode solver. I access it one row at a time. I don't have direct access to the data because it is in an object called an N_Vector. So I access it something like this

realtype *udata;
udata = NV_DATA_P(u);
for (n=0; n<my_length; n++)
  printf("%5.4Lf\t", udata[n]);

Note that realtype is probably a long double and a one line C code returned that sizeof(long double) is 16 (bytes) and my system is little endian (does that even matter?).

I can't find the definition of NV_DATA in the documentation.

Note also that I want to save the entire precision (not just the four decimals in the printf statement).

Thanks.

Answer 1

[Sachin Ganjare]

If you are importing from .dat file, refer below link:

http://www.mathworks.com/matlabcentral/newsreader/view_thread/82442

Else could you please provide format of file wherein this matrices data reside?

Hope it helps!!!

[Jeff]

Please see my comment to the main question for more details (I know, I really didn't provide much at all). I have a long running program which generates data (from an ode solver). I want to save all of the data and import it into MATLAB for analysis. I think the link you provide will help. It is probably best for me to write the data to a file, which I can sneaker-net (remember that term everyone?) to the MATLAB machine.