gistfile1.txt

#using distance formula
planesDist <- function(x1, x2, x3, y1, y2, y3) {   

        dist <- function(s1, s2, s3, s4) {
        d <- sqrt(
        t(x1 + s1*x2 + s2*x3 - (y1 + s3*y2 + s4*y3)) %*% 
        (x1 + s1*x2 + s2*x3 - (y1 + s3*y2 + s4*y3))) 
        return(d)}  

   start <- cbind(seq(-100,100,.01),seq(-100,100,.01),seq(-100,100,.01),seq(-100,100,.01)) 

   m<-min(mapply(function(s1,s2,s3,s4) nlm(dist,s1,s2,s3,s4)$minimum,start[,1],start[,2],start[,3],start[,4]))

return(m)}

x.1 <- c(-2,1,0,1)
x.2 <- c(1,-1,1,0)
x.3 <- c(0,0,1,0)

y.1 <- c(0,1,0,0)
y.2 <- c(1,0,2,1)
y.3 <- c(0,0,0,0)

planesDist(x.1,x.2,x.3,y.1,y.2,y.3)