[Scilab-Dev] empty sparse: sparse([]) vs sparse([],[],[0 0])

[Samuel Gougeon]

Hello,

In Scilab 5.5 and up to Scilab 6.0.1, there was no empty sparse. Trying 
to build it yielded [] :

--> sparse([])
  ans  =
      []
--> sparse([],[],[0 0])
  ans  =
      []

However, in the 6.0 branch, the second statement now creates an empty 
sparse:

--> sparse([],[],[0 0])
  ans  =
(  0,  0) zero sparse matrix

while we still have

--> sparse([])
  ans  =
      []

I am wondering if this change is intentional, because it does not look 
documented.
I am not really able to assess the impact of this change.
I have the feeling that it's rather useful to be able to have an empty 
sparse. This enables the fact that, from a sparse, deletions -- possibly 
down to empty -- and then further insertions can be done without loosing 
the sparse encoding.
However, i think that, if this is kept for Scilab 6.0.2, then still 
getting [] out of sparse([]) instead of getting the empty sparse becomes 
rather inconsistent and should be changed as well.

Looking forward to reading you about this topic

Samuel