This is an R code for which I need the following answers, please help! Needs to be conducted in R only! This is literally the whole question.

recpart_fwd <- function(y,x,Mmax){ N <- length(y) # sample size n <- ncol(x) # number of predictors B <- init_B(N,Mmax) # Exercise: write init_B() splits <- data.frame(m=rep(NA,Mmax),v=rep(NA,Mmax),t=rep(NA,Mmax)) #--------------------------------------------------- # Looping for forward selection: for(M in 1:Mmax) { # contrast to indexing 2...Mmax in Friedman lof_best <- Inf for(m in 1:M) { # choose a basis function to split for(v in 1:n){ # select a variable to split on browser() tt <- split_points(x[,v],B[,m]) # Exercise: write split_points() for(t in tt) { Bnew <- data.frame(B[,(1:M)[-m]], Btem1=B[,m]*(x[,v]>t),Btem2=B[,m]*(x[,v]<=t)) gdat <- data.frame(y=y,Bnew) lof <- LOF(y~.,gdat) # Use your LOF() from week 4 if(lof < lof_best) { lof_best <- lof splits[M,] <- c(m,v,t) # will } # end if } # end loop over splits } # end loop over variables n <- n-1 } # end loop over basis functions to split m <- splits[M,1]; v <- splits[M,2]; t <- splits[M,3] B[,M+1] <- B[,m]*(x[,v]<=t) B[,m] <- B[,m]*(x[,v]>t) } # end loop over M return(list(B=B,splits=splits)) } H <- function(x) { return(as.numeric(x>=0)) } LOF <- function(form,data) { ff <- lm(form,data) return(sum(residuals(ff)^2)) } #------------------------------------- #if(Mmax<2) { # warning("Input Mmax must be >= 2; setting to 2") # Mmax <- 2 # } init_B <- function(N,Mmax) { B <- data.frame(matrix(NA,nrow=N,ncol=(Mmax+1))) B[,1] <- 1 names(B) <- c("B0",paste0("B",1:Mmax)) return(B) } split_points <- function(xv,Bm) { out <- sort(unique(xv[Bm>0])) return(out[-length(out)]) } set.seed(123); n <- 10 x <- data.frame(x1=rnorm(n),x2=rnorm(n)) y <- rnorm(n) rp <- recpart_fwd(y,x,Mmax=9) QUESTIONS TO RESOLVE! Insert a `browser()` at line 12 of `recpart_fwd()` (just inside the for loop over v) and run the function. i. When `browser()` stops the function, print out the value of v and n. ii. Step through the function with `n` a few times and then type `c` to continue execution to the next call to `browser()`. Print v again. iii. Use `f` to finish execution of the v-loop. Print v again. Repeat a few times until the function stops. What was the value of v just before the crash?

iv. Remove your `browser()` and type `debug(recpart_fwd)`. Now run the function under the debugger. Type out the value of a few of the variables as you go. When you are done, type `undebug(recpart_fwd)` to stop debugging.

v. Insert `print()` or `cat()` statements at around line 12 of `recpart_fwd()` to print out the values of `v` and `n`. Re-run `recpart_fwd()`.