I am switching from Matlab to R, but I found that R is 200 times slower than
matlab.
Since I am newbie to R, I must be missing some important programming tips.
Please help me out on this.
Here is the function:
## make the full pair-wise permutation of a vector
## input_fc=c(1,2,3);
## output_fc=(
1 1 1 2 2 2 3 3 3
1 2 3 1 2 3 1 2 3
);
grw_permute = function(input_fc){
fc_vector = input_fc
index = 1
k = length(fc_vector)
fc_matrix = matrix(0,2,k^2)
for(i in 1:k){
for(j in 1:k){
fc_matrix[index] = fc_vector[i]
fc_matrix[index+1] = fc_vector[j]
index = index+2
}
}
return(fc_matrix)
}
For an input vector of size 300. It took R 2.17 seconds to run.
But the same code in matlab only needs 0.01 seconds to run.
Am I missing sth in R.. Is there a away to optimize. ???
Thanks
--
Zhandong Liu
Genomics and Computational Biology
University of Pennsylvania
616 BRB II/III, 421 Curie Boulevard
University of Pennsylvania School of Medicine
Philadelphia, PA 19104-6160
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