Is there any obligation for authors of a paper to provide the dataset used in their research, upon request? I've recently read a curious article on machine learning where the author used a very interesting dataset, which would normally take thousands of man-hours to recreate. Now, assuming I would like to either:


Recreate the author's results, or 
Improve upon them


Does the author have any obligation to provide me with said dataset?

N.B. In this particular situation the author has declined my request
Inherently? No. While it might be good for science generally, they're under no obligation to do so.

That being said, some funding agencies require data be made available as a condition of their support, and some journals require it as a condition of publication. Absent that though, there's no obligation to do so.