There was an error in the function f -- it only worked correctly if
order was 1. Here it is with that fixed. The function f is the
only thing changed from my last post. It makes use of the
fact that sum(x) == n and sum(x*x) == n*n only occur when
one element of x is n and the rest are 0.
root3
Thought about this some more and here is a solution that
works with 2d and 3d (and higher dimensions).
inner is a generalized inner product similar to a function
I have posted previously and f(x,y) is an inner product such
that f(x,y) is TRUE if abs(x - y) == order (after converting
both x and y t
For 2d here is a solution based on zoo. It turns the matrix into
a time series and lags it forwards and backwards and does the
same for its transpose in order to avoid index machinations.
The function is called rook2 and it first defines three local
functions, one that converts NAs to zero, one th
Jason
-Original Message-
From: Pontarelli, Brett [mailto:[EMAIL PROTECTED]
Sent: Friday, February 17, 2006 4:04 PM
To: Mills, Jason; r-help@stat.math.ethz.ch
Subject: RE: [R] Matrix indexing in a loop
Do you have to use a loop? The following function should do what you want for
the
Mills, Jason
Sent: Friday, February 17, 2006 1:36 PM
To: r-help@stat.math.ethz.ch
Subject: [R] Matrix indexing in a loop
How do you specify matrix location a[i,j] (or a[i-1,j], etc.) in a "for"
loop?
I am looking for a flexible method of indexing neighbors over a series of lags
(1,2,
How do you specify matrix location a[i,j] (or a[i-1,j], etc.) in a "for"
loop?
I am looking for a flexible method of indexing neighbors over a series
of lags (1,2,3...) and I may wish to extend this method to 3D arrays.
Example:
Data matrix
> fun
[,1] [,2] [,3]
[1,]159
[2,]
