help-octave
[Top][All Lists]

## Re: matrix of variables?

 From: Heber Farnsworth Subject: Re: matrix of variables? Date: Fri, 30 May 2003 17:51:00 -0500

Define x as a vector and then reshape it into a matrix within the function.
```
x = reshape(x,5,5);

Heber Farnsworth

On Friday, May 30, 2003, at 05:12 PM, jdonner wrote:

```
```Hi,

I'm trying to solve a non-linear equation with 25 vars,
and it works when I number them from x(1) .. x(25) but,
```
they naturally are a 2D array of variables, is there some way I can I use matrix notation for convenience?
```When I try to say this:
function y = f (x)
g = 0.9;
# center parts
y(2,2) = -1 * x(2,2) + (1/4)*g*(x(1,2) + x(2,1) + x(2,3) + x(3,2));
y(2,3) = -1 * x(2,3) + (1/4)*g*(x(1,3) + x(2,2) + x(2,4) + x(3,3));
... more

I get:
error: invalid column index = 2
error: evaluating binary operator `*' near line 4, column 13
error: evaluating binary operator `+' near line 4, column 22
error: evaluating assignment expression near line 4, column 8
error: called from `f'
error: fsolve: evaluation of user-supplied function failed

Is there a way to do this?
Thanks,

Jeff

-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------

```
```

-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------

```