Hello,
In GAP everything is coherent: permutations are based on 1..n and
arrays start at 1. Note that, in the background, permutations are
stored as a C array of ints on 0..n-1. But the C code is inaccesible
from the console and everything is nice from both the programmer and
user point of views.
If we start having Permutations0 and Permutations1 why not list0,
list1, tuple0, tuple1, etc? For me it does not looks like a solution.
As Sage is built on Python the only coherent way to define
permutations is on 0..n-1. Nevertheless, it is nice and useful to have
permutations on other domains like 1..n or {a,b,c}. What do you think
about the following for action on matrices/vectors/etc
class Matrix:
def permutation_action_on_rows(self, s):
D = s.parent().domain().cardinality()
if not D.cardinality() == self.nrows(): raise ValueError
s0 = s.as_perm_on_0_n() # might raise an Error if
# D is not totally ordered
self._permutation0_action_on_rows(s0)
Vincent
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-devel+unsubscr...@googlegroups.com.
To post to this group, send email to sage-devel@googlegroups.com.
Visit this group at http://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
