dissimilarity structure

From: Francois Deshaies 

How can I easily convert this format

INT CAB 1.0000000
LIG CAB 0.3333333
TEN CAB 1.0000000
INT LIG 1.0000000
TEN LIG 1.0000000
INT TEN 0.0000000
 
to this dissimilarity structure  format(compatible with hclust) ?
 
          CAB INT LIG
INT 1.0000000        
LIG 0.3333333   1    
TEN 1.0000000   0   1
 
(and vice versa)
 
Thanks

---------------------------

To convert from the vector to an interaction matrix
(which may not be the best form for the dissimilarity matrix...)

x

V1  V2        V3
1 INT CAB 1.0000000
2 LIG CAB 0.3333333
3 TEN CAB 1.0000000
4 INT LIG 1.0000000
5 TEN LIG 1.0000000
6 INT TEN 0.0000000

a <- unique (x$V1)
b <- unique (x$V2)
ij <- cbind (match (x$V1, a), match (x$V2, b))
d <- matrix (0, nrow=length(a), ncol=length(b))
dimnames(d) <- list (a, b)
d[ij] <- x$V3
d

CAB LIG TEN
INT 1.0000000   1   0
LIG 0.3333333   0   0
TEN 1.0000000   1   0


Denis White
   US EPA, 200 SW 35th St, Corvallis, Oregon, 97333 USA
   voice: 541.754.4476, email: white.denis at epa.gov
   web: www.epa.gov/wed/pages/staff/white/

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