MATLAB: Reading .mat files

mat

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<5735×1033 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?

Best Answer

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.
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