On 09/04/2012 12:32 PM, James Lenihan wrote:
I found this example in an Introductory R book in the chapter on Matrices and
Arrays

You should probably check with the author of the book (there might be an errata page posted somewhere), but it looks like a typo, in your code or the original:

The array is
>  m
      [,1] [,2] [,3] [,4] [,5]
[1,]    0   12   13    8   20
[2,]   12    0   15   28   88
[3,]   13   15    0    6    9
[4,]    8   28    6    0   33
[5,]   20   88    9   33    0

The code is

#returns the minimum value of d[i,j], i !=j and the row attaining
#the minimum, for square symmetric d; no special policy on ties
mind<- function(d) {
      n<- nrow(d)
      # add a column to identify row number for apply()
      dd<- cbind(d,1:n)
      wmins<- apply(dd[-n,],1,imin)
      # wins will be 2 X n, 1st row being indices and 2nd being values
      i<- which.min(wmins[2,])
      j<- wmins[1,i]
      return(c(d[i,j],i,j))
}

#this finds the location, value of the minimum in a row x
imin<- function(x) {
    lx<- length(x)
     i<- x[lx] # original row number
     j<-which.min(x[(x+1):(lx-1)])

That line doesn't make sense. Putting i in place of the innermost x would make more sense, but wouldn't work in all cases: if i == lx, you'll get a garbage answer.

Duncan Murdoch
     k<- i+j
     return(c(k,x[k]))
}
The result s/b
[1] 6 3 4

I am getting:

Warning messages:
1: In (x + 1):(lx - 1) :
   numerical expression has 6 elements: only the first used
2: In (x + 1):(lx - 1) :
   numerical expression has 6 elements: only the first used
3: In (x + 1):(lx - 1) :
   numerical expression has 6 elements: only the first used
4: In (x + 1):(lx - 1) :
   numerical expression has 6 elements: only the first used

I have check my typing a number of times.

Does anyone see an error?

Thanks,

Jim L.
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