Symmetric MAPE following visualization in Figure 3c of the MAAPE Paper

symmetric-MAPE.r

library(dplyr)
library(ggplot2)

A <- seq(0, 10, length=100)
F <- seq(0, 10, length=100)

symmetric_mape <- function(A, F) {
  abs(F - A) / (abs(A) + abs(F))
}

smape_grid <- tbl_df(expand.grid(A=A, F=F)) %>%
  mutate(smape=symmetric_mape(A, F))

p <- ggplot(smape_grid, aes(x=A, y=F)) + geom_raster(aes(fill=smape))
p <- p + scale_fill_gradientn(colors=c("#0000FFFF","#FFFFFFFF","#FF0000FF"))
p + ggtitle("Visualization of SMAPE in 2D")