Date: Nov 7, 2013 3:38 PM
Author: Curious
Subject: Re: matrix from random selected data
"dony" wrote in message <l5fded$qdf$1@newscl01ah.mathworks.com>...

> hai,

> I have some problem

> and i need help

> i have matrix in 100x100, and from this matrix i have some random selected data.

> from this data, i want to make it(selected data) to be a center of 3x3 new matrix

> and then from this new matrix i want to calculate mean and standart deviation.

> thanks for help

% The last part should be simple

% If A is your 3X3 "new" matrix, then

mean(A)

% or

mean(A(:))

% or some variation of that should give your mean value.

% Use std in the same way to get the standard deviation

doc mean

doc std

% Its not clear from your description how the "new"

% matrix is derived from the original 100X100 matrix.

% Can you provide an example?

% I'm guessing that if ii & jj are a location within

% your 100X100 matrix (call it X) then perhaps:

A = X((ii-1):(ii+1),(jj-1):(jj+1))

% might be what you want.

% Note: the above requires 1<ii,jj<100

% (can't be an edge).