[R] Help on sound identification of "distance between lines"

[Andras Farkas]

Dear List

I would like to ask for some input on the following (here is a simplified version of the code):

t <-t(seq(0,120,by=120/48))
d <-500
k <-0.1
x <-matrix((d/20)*exp(-k*0.9*t))
y <-matrix((d/15)*exp(-k*0.7*t))
z<-matrix((d/22)*exp(-k*1.1*t))
w<-matrix((d/17)*exp(-k*0.2*t))
t <-matrix(seq(0,120,by=120/48))
plot(t,x,type="l",ylab="Response",xlab="Time (h)")
lines(t,y,col="green")
lines(t,z,col="blue")
lines(t,w,col="yellow")
sim <-t(cbind(x,y,z,w))
true <-t((d/19)*exp(-k*0.35*t))
lines(t,true,col="red")

#find closest line
M <- rbind(sim, true) 
D <- as.matrix(dist(M)) 
diag(D) <- NA 
which.min(tail(D, 1))

In reality sim will consist of 5000 rows. My goal here is to use a sound method to find the row in sim that is most identical or closest to true (represented by the red line in the plot) taking into consideration the whole time interval evaluated. 

as always, thanks for the input...

Andras