From: <HIDDEN>
Newsgroups: comp.soft-sys.matlab
Subject: Re: IncoHerences in MATLAB
Date: Fri, 12 Dec 2008 23:24:01 +0000 (UTC)
Organization: The MathWorks, Inc.
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NZTideMan <> wrote in message <>...
> On Dec 12, 12:37=A0pm, "Trouble Finders Costa"
> <> wrote:
> > I have discovered some incoerences and troubles in some commands of MATLA=
> B. These problems caused me headaches by the time I have faced them for the=
>  first time, because of the loss of several minutes in work until the perce=
> ption of the problem.
> >
> > One of this problems, an incoerence, is: try if [125000:125000:10/0.00001=
> ] and [125000:125000:1000000] are vectors of the same dimension when genera=
> ted in MATLAB.
> >
> > Another problem, a trouble, has to do with the question of numerical prec=
> ision. Try the following commands:
> > time =3D 0; time_increment =3D 0.01; n =3D (a number of your choice);
> > for i =3D 1:n
> > =A0 =A0 time =3D time =A0+ time_increment;
> > end
> >
> > You will notice that, for large values of "n", some decimal numbers will =
> appear after the second one. This shouldn't happen. I have observed this pr=
> oblem for values of "time_increment" less than 0.1
> >
> > Thank you for your attention.
> >
> > Dante Valen?a.
> What do you mean by "incoerence"?  You've written it 3 times, so it
> cannot be a spelling mistake, but it is not an English word.  I
> suspect it is a malapropism, but I'm not sure which word you're
> getting at.
> "incoherence", means a nonsense, but the fact that 10/0.00001 is not
> the same as 1000000 in floating point arithmetic is not a nonsense.
> The principle is well known and has been commented on many times in
> this forum.
> That these matters cause you headaches is a shame, but perhaps they
> would cause you less concern if you learned from your mistakes and in
> future refrained from trying to use floating point numbers as if they
> were integers.

Thank you. I was having in mind the word "incoer?ncia" when I wrote "incoerence". I will try to improve my English, it's not my first language. Is it yours?