RE: Some Octave newbie questions regarding number format and matrices

[dastew]

> Date: Sat, 19 Sep 2009 08:24:53 -0700
> From: address@hidden
> To: address@hidden
> Subject: Some Octave newbie questions regarding number format and matrices
>
>
> Hi,
>
> I started using Octave very recently and am still unsure about a few things:
>
> 1. is there any way to force octave to express numbers in fraction form, to
> avoid loss of precision?

I am not sure but I don't think there is.


>
> 2. when I want to computer the inverse of a matrix, I have to do inv(A'),
> computing the inverse of the transpose, in order to get the correct answer.
> Why is that?
>

When I do what you say I don't have to do the transpose.: so : What version Of octave do you have and what operating system are you running it on?

example:

octave-3.0.1:1> a= [1 2; 7 3]
a =

   1   2
   7   3

octave-3.0.1:3> b=inv(a)
b =

  -0.272727   0.181818
   0.636364  -0.090909

octave-3.0.1:4> a*b
ans =

   1.00000   0.00000
   0.00000   1.00000

octave-3.0.1:5>


Doug Stewart



> thank you
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