dat<-data.frame(x=c(2,3,4,5,6),y=c(4,4,6,6,10))

N = length(dat$x)
x<-dat$x
y<-dat$y

ols<-lm(y~x)
summary(ols)

min.RSS <- function(pa1, pa2, x, y, N) {
  b0 = pa1
  b1 = pa2
  RSS = vector("numeric",length(b1))
  for (i in 1:length(b1)){
    RSS[i] = sum((pa1[i]+pa2[i]*x-y)^2)
  }
  return(RSS)
}

pa1 <- seq(0.1, 1.1, by=0.05)
names(pa1) <- pa1
pa2 <- seq(1, 2, by=0.05)
names(pa2) <- pa2

z.RSS <- outer(X = pa1, Y = pa2, FUN = min.RSS, N = N, x = x, y = y)
min(z.RSS)
zd.RSS<-data.frame(z.RSS)

inds_0 = which(zd.RSS == min(zd.RSS), arr.ind=TRUE)
inds_0
(rnames = rownames(zd.RSS)[inds_0[,1]])
(cnames = colnames(zd.RSS)[inds_0[,2]])

require(lattice)
#Loading required package: lattice
wireframe(z.RSS, drape=T, xlab="b0", ylab="b1", zlab="RSS",col.regions=rainbow(100))
wireframe(z.RSS, xlab="b0", ylab="b1", zlab="RSS")