CODEWITHSUNDEEP
rmatrix
Leonardo
Leonardo

Reputation: 19

Filling matrix in R without for loops

I am a beginner in R and i know the way i have done is wrong and slow. I would like to fill a matrix and i need to compute each term. I have tried two for loops, here is the code. Do you know a better way to do it?

KernelGaussianMatrix <- function(x,delta){
  Mat = matrix(0,nrow=length(x),ncol=length(x))
  for (i in 1:length(x)){
   for (j in 1:length(x)){
     Mat[i,j] = KernelGaussian(x[i],x[j],delta)   
   } 
  } 
  return(Mat)
}

Thx

Upvotes: 1

Views: 1220

Answers (2)

Jthorpe
Jthorpe

Reputation: 10203

you want to use the function outer as in:

Mat <- outer(x,x,KernelGaussian,delta)

note that any arguments after the third argument in outer are provided as additional arguments to the function provided as the third argument to outer

Upvotes: 2

Donbeo
Donbeo

Reputation: 17647

If a for loop is required to generate the values than your method is fine.

If the values are already in an array values you can try mat = matrix(values, nrow=n, ncol=p) or something similar.

Upvotes: 0

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