Thread Subject: rotations and reflections in matlab

How can i check whether a matrix is a reflection / obtained by rotation / combination of rotation and reflection of another matrix ?

eg: [ 1 2 ] on vertical reflection gives [ 2 1 ] which on -90 deg. rotation
       [ 5 4 ] [ 4 5 ]

    gives [ 1 5 ]
             [ 2 4 ]

Also, how can I find reflection of a matrix along main-diagonal & off-diagonal.

"Midhun " <midhunjoyp@gmail.com> wrote in message <h6juit$et5$1@fred.mathworks.com>...
> How can i check whether a matrix is a reflection / obtained by rotation / combination of rotation and reflection of another matrix ?
>
> eg: [ 1 2 ] on vertical reflection gives [ 2 1 ] which on -90 deg. rotation
> [ 5 4 ] [ 4 5 ]
>
> gives [ 1 5 ]
> [ 2 4 ]
>
> Also, how can I find reflection of a matrix along main-diagonal & off-diagonal.

Take QR decomposition, nd check if abs(R) is "close" to identity.

Bruno