help-octave
[Top][All Lists]

## Re: boundary value + eigen value problem

 From: Geordie McBain Subject: Re: boundary value + eigen value problem Date: Fri, 15 Oct 2004 10:10:45 -0400

```Once you've discretized the ODE, so that H is a known square matrix, Si
is an unknown column vector (eigenvector), and E is an unknown number
(eigenvalue), you can use the octave function eig, which is described in
the manual under `Linear Algebra/Basic matrix functions', basically, E =
eig (H).

One way to discretize two-point boundary value problems like this is
orthogonal collocation.  For this, use the octave function colloc,

As noted at ScaryOctave

http://wiki.octave.org/wiki.pl?OrthogonalCollocation

there are some good examples of the use of colloc for 2-pt BVPs in the
book `Chemical Reactor Analysis and Design Fundamentals' by J. B.
Rawlings & J. G. Ekerdt (Nob Hill, 2002).

Hope this helps,

Geordie McBain

On Thu, 2004-10-14 at 03:24, Y U Sasidhar wrote:
> Which octave function can be used to solve equations of type:
>
> k*Si(x)''+V(x)*Si(x)=E*Si(x)
> with  Si(0)=value1; Si(10)=value2
> Si'' -- second drivative of Si
> ( this is a form of Schrodinger equation H Si = E Si )

-------------------------------------------------------------
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
-------------------------------------------------------------

```