[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Numeric issue
From: |
JokerOne |
Subject: |
Numeric issue |
Date: |
Fri, 4 Jul 2014 02:46:22 -0700 (PDT) |
Hi community,
I using Octave for quite a while now, however, apparently, I am not aware of
some numeric issues going on, which is where I like to ask you for help:
Basically, I noticed, that in the following dummy code, the results appear
strange to me:
clear all;
format long;
a = [1.1:1.1:100];
a(50) % expected to be == 55
b = 50*1.1; % expected to be == 55
((a(50)-b) == 0) % is 1
((a(50)-55) == 0) % is 0 (!?)
ceil(a(50)) % expected to be == 55, but results in 56 ??
ceil(b) % same as above ??
ceil(55) % == 55, as expected
-->
ans = 55.0000000000000
ans = 1
ans = 0
ans = 56
ans = 56
ans = 55
also,
"
a
"
results in:
[...]
Columns 49 through 52:
53.90000000000001 55.00000000000001 56.10000000000000
57.20000000000000
[...]
with a strange result for 55 --> 55.00000000000001
I guess, all this is known to you experts. Do you have a good advice for me,
how to cope with such numeric issues, when exact results are important?
I am using Octave 3.8.1 on a Win7 machine, btw.
Any help is appreciated
Max
--
View this message in context:
http://octave.1599824.n4.nabble.com/Numeric-issue-tp4665228.html
Sent from the Octave - General mailing list archive at Nabble.com.
- Numeric issue,
JokerOne <=