Re: concat([])

[Karim Belabas <Karim.Belabas@math.u-bordeaux.fr>]

* Max Alekseyev [2014-07-08 00:34]:
> ? concat([])
>   ***   at top-level: concat([])
>   ***                 ^----------
>   *** concat: domain error in concat: vector = []
>   ***   Break loop: type 'break' to go back to GP prompt
> 
> 
> Should it simply return [] ?

No, see ??concat
[...]
  If  y  is  omitted,   x has to be a row vector or a list,  in which case its
  elements are concatenated, from left to right, using the above rules.
[...]


concat([x_1,...,x_n]  /* single vector */) is *defined* as the
following concatenation of all elements in the set:

  concat(concat((concat(x_1,x_2), x_3) ..., x_n)

You're trying to concatenate the elements of the empty set. This is undefined
just like e.g. vecmax would be.

Cheers,

    K.B.
--
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
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