--- a
+++ b/R/loss_functions_plot.R
@@ -0,0 +1,52 @@
+# loss_functions_plot.R
+require(ggplot2)
+require(cowplot)
+
+plot_activation_function <- function(f, title, range, target){
+  ggplot(data.frame(x=range), mapping=aes(x=x)) + 
+    geom_hline(yintercept=0, colour='red', alpha=1/4) +
+    geom_vline(xintercept=0, colour='red', alpha=1/4) +
+    stat_function(fun=f, colour = "dodgerblue3",) +
+    ggtitle(title) +
+    theme(text = element_text(size = 16), plot.title = element_text(hjust = 0.5), axis.text.x = element_text(angle=45, hjust = 1)) +
+    xlab("Prediction") + ylab("Loss") +
+    scale_x_continuous(breaks=c(0, target, 0.25, 0.5, 0.75, 1))
+}
+
+plot_all_activation_functions <- function(f1, f2, f3, title, range, target){
+  ggplot(data.frame(x=range), mapping=aes(x=x)) + 
+    geom_hline(yintercept=0, color='red', alpha=1/4) +
+    geom_vline(xintercept=0, color='red', alpha=1/4) +
+    stat_function(fun=f1, aes(colour = "MSE")) +
+    stat_function(fun=f2, aes(colour = "MAE")) +
+    stat_function(fun=f3, aes(colour = "RMSE")) +
+    ggtitle(title) +
+    theme(text = element_text(size = 18, face = "bold"),
+          plot.title = element_text(hjust = 0.5),
+          axis.text.x = element_text(angle=45, hjust = 1),
+          legend.position = "top") +
+    xlab("Prediction") + ylab("Loss") +
+    scale_x_continuous(breaks=c(0, target, 0.25, 0.5, 0.75, 1)) +
+    scale_colour_manual("", 
+                        breaks = c("MSE", "MAE", "RMSE"),
+                        values = c("MSE"="dodgerblue3", "MAE"="red3", "RMSE"="orange1"))
+    
+}
+
+set.seed(42)
+yhats <- runif(32, min=0, max=1)
+mse <- function(yhats, y=0) {((y - yhats) ** 2)/2}
+p_mse <- plot_activation_function(mse, 'MSE', c(0,1), 0)
+  
+mae <- function(yhats, y=0) {abs(y - yhats)/2}
+p_mae <- plot_activation_function(mae, 'MAE', c(0,1), 0)
+
+rmse <- function(yhats, y=0) {sqrt(((y - yhats) ** 2)/2)}
+p_rmse <- plot_activation_function(rmse, 'RMSE', c(0,1), 0)
+
+plot_all_activation_functions(mse, mae, rmse, '', c(0,2), 0)
+ggsave("Plots/All_Loss_Functions_Plot.pdf")
+
+p_grid <- cowplot::plot_grid(p_mse, p_mae, p_rmse, ncol = 3)
+  # theme(plot.margin = unit(c(1,31,3,3), "lines"))
+ggsave("Plots/Loss_Function_Plots.pdf", plot = p_grid)