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[Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek fo
From: |
Rik |
Subject: |
[Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility |
Date: |
Fri, 24 Sep 2021 18:05:05 -0400 (EDT) |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36 |
Follow-up Comment #24, bug #61199 (project octave):
@Anonymous: Matlab gives no warnings for nchoosek (54,27) and nchoosek
(56,28). The results are the same for Matlab and for unpatched Octave, so it
is not clear that the improved code with gcd() is necessary for these cases.
In Matlab, nchoosek (58,29) does produce a warning. Specifically, "Warning:
Result may not be exact. Coefficient is greater than 9.007199e15 and is only
accurate to 15 digits.
The result is the same in either Matlab or Octave
format long
z = nchoosek (58,29)
z = 3.006726649954106e+16
+verbatim-
With the patched code that uses gcd() the answer differs by 2 in the last
position
z = 3.006726649954104e+16
There are some differences. For Matlab and Octave unpatched code,
nchoosek (56,26)
ans = 6.646448384109071e+15
BUT, for patched code
nchoosek (56,26)
ans = 6646448384109072
There is a difference of 1 in the final position. This is correct as the
answer should be even. But, is it worth it? eps (6.646448384109071e+15) is 1
so essentially the current calculation is within the error bar for a numerical
approximation. I don't have much of an opinion here.
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- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, (continued)
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, John W. Eaton, 2021/09/23
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, Rik, 2021/09/23
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, Nicholas Jankowski, 2021/09/23
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, Nicholas Jankowski, 2021/09/23
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, John W. Eaton, 2021/09/23
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, Philip Nienhuis, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, Rik, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility,
Rik <=
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, Rik, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, John W. Eaton, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, Rik, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, anonymous, 2021/09/24
- [Octave-bug-tracker] [bug #61199] Allow 'char' input sets to nchoosek for Matlab compatibility, Rik, 2021/09/25