Hi, I just started to use R for my Phd. I have to write a Formula by witch, given two matrices of vectors (electrostatic potential map) I shall calculate the similarity between them. Could you please tell me if I'am doing it right. The complecte formula is attached to an image file the script #!/usr/bin/env Rscript options(max.print=2000000) x<-read.table("a") #reading the matrix 'a' y<-read.table("b") #reading the matrix 'b' #---------------------------------- # based on Chris et al (2011): The effect of electrostatics on Factor H and related pathologies c1<-x-y # phiA(i,j,k)-phiB(i,j,k) c<-sqrt(c1$V1^2+c1$V2^2+c1$V3^2) # |phiA(i,j,k)-phiB(i,j,k)| a<-sqrt(x$V1^2+x$V2^2+x$V3^2) #|phiA(i,j,k)| b<-sqrt(y$V1^2+y$V2^2+y$V3^2) #|phiB(i,j,k)| #---------------------------------- esdi<-c/max(a,b) #|phiA(i,j,k)-phiB(i,j,k)|/max(|phiA(i,j,k)|,|phiB(i,j,k)|) esd<-(1/1391093)*sum(esdi) # 1/N E*|phiA(i,j,k)-phiB(i,j,k)|/max(|phiA(i,j,k)|,|phiB(i,j,k)|) esd Best wishes Houcemeddine OTHMAN Pasteur Institute of Tunis Venom and biotheurapetical Molecules Lab -------------- next part -------------- A non-text attachment was scrubbed... Name: similarity_formula.png Type: image/png Size: 7939 bytes Desc: similarity_formula.png URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20120620/e981e71e/attachment.png>