ranges?

[John W. Eaton]

On 22-Aug-2006, Dmitri A. Sergatskov wrote:

| I thought that ranges used to be a different class. But I just noticed that in
| 2.9.7 is is shown as "double" Is it OK?
| 
| octave:1> idx = (1:10)
| idx =
| 
|    1   2   3   4   5   6   7   8   9  10
| 
| octave:2> whos idx
| 
| *** local user variables:
| 
|   Prot Name        Size                     Bytes  Class
|   ==== ====        ====                     =====  =====
|    rwd idx         1x10                        24  double
| 
| Total is 10 elements using 24 bytes
| 
| octave:3> a = idx *1
| a =
| 
|    1   2   3   4   5   6   7   8   9  10
| 
| octave:4> whos a
| 
| *** local user variables:
| 
|   Prot Name        Size                     Bytes  Class
|   ==== ====        ====                     =====  =====
|    rwd a           1x10                        80  double
| 
| Total is 10 elements using 80 bytes

Class must be double for compatibilty.  Internally, Octave still has a
special data type to represent ranges.  That's why you see only 24
bytes used in the first case.  Most (all?) arithmetic operations on
ranges result in matrices though, so that's why you see 80 bytes used
in the second case.  Adding optimized operations for ranges is
possible, but someone has to do the work.

See also the typeinfo function, which returns the name of the internal
data type instead of the Matlab-compatible class name.

jwe