#5415: wrong definition of multifactorial?
------------------------------+---------------------------------------------
Reporter: cwitty | Owner: robertwb
Type: defect | Status: new
Priority: major | Milestone: sage-4.1.1
Component: basic arithmetic | Keywords:
Reviewer: | Author:
Merged: |
------------------------------+---------------------------------------------
Comment(by jhpalmieri):
I think the problem is that not enough factors are included. Actually,
there are two problems: in the base case, it should return n, not 1; that
is, make this change:
{{{
# base case
if 0 < n < k:
- return ONE
+ return n
}}}
After making this change, I'm still getting the wrong answers for
{{{a.multifactorial(3)}}} whenever a is congruent to 2 mod 3 (except for
a=2), and for {{{a.multifactorial(4)}}} whenever a is congruent to 2 or 3
mod 4 (except for a=2,3). It seems that not enough factors are used; for
example, 10.multifactorial(4) should be 10 x 6 x 2 = 120, but Sage
computes it as 10 x 6 = 60.
If we fix this, we can put in doctests like the following:
{{{
sage: L = sloane_sequence(6882)[2] # optional - internet
Searching Sloane's online database...
sage: all([Integer(a).multifactorial(2) == L[a] for a in range(1,20)])
# optional - internet
True
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5415#comment:2>
Sage <http://sagemath.org/>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en
-~----------~----~----~----~------~----~------~--~---
