Since it is not clear exactly what you require, I have assumed that what you
are looking for is the minimum value for each row or column depending upon
which is airports and which is the towers.
Is this what you are looking for
x - runif(100)
dim(x) - c(5,20)
apply(x,1,function(y) which(y == min(y)))
The only issue I see here is that there may be more than one minimim in which
case the value returned will be a list with all of the matched values which
would need to be processed
x - trunc(runif(100) * 10)
dim(x) - c(5,20)
apply(x,1,function(y) which(y == min(y)))
If you did not have a method for processing you could order the towers in some
preferred order and just take the first match
apply(x,1,function(y) head(which(y == min(y)),1))
If you are talking about a matrix where you need to find the shortest path, you
might want to look at the package e1071. I think the function is called
allShortestPaths
Tom
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of
Williams, Michael
Sent: Monday, 18 April 2005 7:58 AM
To: r-help@stat.math.ethz.ch
Subject: [R] Minimum distance
G'day, I have a matrix 2 x 500 populated with all the distances
between a list of airports and a list of towers. What I'm
having trouble
doing is finding the closest airport to each tower, Any help would be
greatly appreciated.
Regards,
Michael Williams
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