Message-ID: <5569DDA1.2060702@hermes.cam.ac.uk>
Date: 2015-05-30T15:56:17Z
From: Michelle Morters
Subject: zero in alternate elements in alternate rows in matrix
In-Reply-To: <5569D6B2.90207@hermes.cam.ac.uk>
Hi - I'm trying to generate the (toy) matrix below in R. I get the error
message shown below (and no matrix!) and I'm unclear as to why - if
someone could advise as to why, that would be ace. Thank you! Michelle
0.7 0 0.1 0 0.1 0 0 0 0 0 0 0
0.1 0.7 0.1 0.1 0.1 0.1 0 0 0 0 0 0
0.1 0.1 0.7 0 0.1 0 0.1 0 0 0 0 0
0.1 0.1 0.1 0.7 0.1 0.1 0.1 0.1 0 0 0 0
0.1 0.1 0.1 0.1 0.7 0 0.1 0 0.1 0 0 0
0 0.1 0.1 0.1 0.1 0.7 0.1 0.1 0.1 0.1 0 0
0 0 0.1 0.1 0.1 0.1 0.7 0 0.1 0 0.1 0
0 0 0 0.1 0.1 0.1 0.1 0.7 0.1 0.1 0.1 0.1
0 0 0 0 0.1 0.1 0.1 0.1 0.7 0 0.1 0
0 0 0 0 0 0.1 0.1 0.1 0.1 0.7 0.1 0.1
0 0 0 0 0 0 0.1 0.1 0.1 0.1 0.7 0
0 0 0 0 0 0 0 0.1 0.1 0.1 0.1 0.7
cross = 0.1
diag = 0.7
n=12 # to be changed to n=1:100 once the code below is correct
nbe=4
R0=sapply(n,function(x){
m = matrix(0, nrow=x, ncol=x)
for (i in 1:x)
{
for(j in 1:x)
{
if (i==j)
{
m[i,j] = diag
}
else if(j<=i+nbe & j>=i-nbe)
{
m[i,j]=cross
}
}
}
for (i in seq(1,x,2))
{
for (j in seq(i+1,i+nbe,2))
{
m[i,j]=0
}
}
print(m)
max(Mod(eigen(m)$value))
}
)
R0
error message: Error in `[<-`(`*tmp*`, i, j, value = 0) : subscript out
of bounds
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