Reading .mat files

Please take a look at the location: http://scgroup20.ceid.upatras.gr:8000/tmg/

Under SAMPLE OUTPUT, you can download the following: MEDLINE: term-document matrix (5,735 x 1,033), dictionary (5,735 indexing terms), query matrix (30 queries)

They are all in .mat format.

When I import the matfiles in Matlab, it says e.g. A_med<5735x1033 double>

But when I do something like: A = A_med(1:10,1:10)

It is displayed as: A =

   (3,2)        2
   (4,2)        2
   (8,2)        2
   (6,6)        1

What format is this really?

Answer 1

[Walter Roberson]

That display is used for sparse matrices. Sparse matrices are (in current versions) restricted to double precision, or logical.

You can use issparse() to determine whether a matrix is sparse or not.