corn <- rbind(c(1, 0, 0), c(0, 1, 0), c(0, 0, 1), c(1, 0, 0))
  reg <- 2/sqrt(6) * (3 * corn - 1) %*% cbind(c(0,  - sqrt(3), sqrt(3)), c(2, -1, -1))
  plot(0, 0, type = "n", xlim = c(-7, 7), ylim = c(-4, 6), axes=F, xlab="", ylab="")
  text(reg[1, 1] - 0.4, reg[1, 2] + 0.4, name[3], cex = 1.4)
  text(reg[2, 1] - 0.4, reg[2, 2] - 0.4, name[1], cex = 1.4)
  text(reg[3,1] + 0.4, reg[3,2] - 0.4,name[2],cex=1.4)
  lines(reg[, 1], reg[, 2], lty = 1)
网上看到这段代码，不知道reg那行代码是什么意思？求大神赐教！！