Color function for green-red heatmap

updown_colors.R

updown_colors <- function(n = 50, down.col = 1/3, up.col=1, saturation = 1)
{ 
  c(hsv(down.col, saturation, seq(1,0,length=n)), hsv(up.col, saturation, seq(0,1,length=n))) 
}