R is not able to find the function "bt.matching.find" - r

Question

I'm having a problem with implementing the function bt.matching.find from the SIT toolbox which is hosted on Github. After downloading the toolbox following the steps described here, I tried to replicate the code described in this blog
library(SIT.dates)
library(SIT)
objt <- bt.matching.find(Cl(data), normalize.fn = normalize.mean, dist.fn = 'dist.euclidean', plot=T)
R did not find the function, so I tried using spacing to access the function
objt <- SIT:::bt.matching.find(Cl(data), normalize.fn = normalize.mean, dist.fn = 'dist.euclidean', plot=T)
But this time I got a weird error which has nothing to do with any argument in the function
Error in last(data, n.reference) : could not find function "last"
I did research on the function bt.matching.find using the function getAnywhere and here's what I got
getAnywhere("bt.matching.find")
A single object matching ‘bt.matching.find’ was found
It was found in the following places
namespace:SIT
with value
function (data, n.query = 90, n.reference = 252 * 10, n.match = 10,
normalize.fn = normalize.mean.sd, dist.fn = dist.euclidean,
plot = FALSE, plot.dist = FALSE, layout = NULL, main = NULL)
{
data = last(data, n.reference)
reference = coredata(data)
n = len(reference)
query = reference[(n - n.query + 1):n]
reference = reference[1:(n - n.query)]
main = paste(main, join(format(range(index(data)[(n - n.query +
1):n]), "%d%b%Y"), " - "))
n.query = len(query)
n.reference = len(reference)
dist.fn.name = ""
if (is.character(dist.fn)) {
dist.fn.name = paste("with", dist.fn)
dist.fn = get(dist.fn)
}
dist = rep(NA, n.reference)
query.normalized = match.fun(normalize.fn)(query)
for (i in n.query:n.reference) {
window = reference[(i - n.query + 1):i]
window.normalized = match.fun(normalize.fn)(window)
dist[i] = match.fun(dist.fn)(rbind(query.normalized,
window.normalized))
if (i%%100 == 0)
cat(i, "\n")
}
min.index = c()
temp = dist
temp[temp > mean(dist, na.rm = T)] = NA
for (i in 1:n.match) {
if (any(!is.na(temp))) {
index = which.min(temp)
min.index[i] = index
temp[max(0, index - 2 * n.query):min(n.reference,
(index + n.query))] = NA
}
}
n.match = len(min.index)
if (plot) {
dates = index(data)[1:len(dist)]
if (is.null(layout)) {
if (plot.dist)
layout(1:2)
else layout(1)
}
par(mar = c(2, 4, 2, 2))
if (plot.dist) {
plot(dates, dist, type = "l", col = "gray", main = paste("Top
Historical Matches for",
main, dist.fn.name), ylab = "Distance", xlab = "")
abline(h = mean(dist, na.rm = T), col = "darkgray",
lwd = 2)
points(dates[min.index], dist[min.index], pch = 22,
col = "red", bg = "red")
text(dates[min.index], dist[min.index], 1:n.match,
adj = c(1, 1), col = "black", xpd = TRUE)
}
plota(data, type = "l", col = "gray", LeftMargin = 1,
main = iif(!plot.dist, paste("Top Historical Matches for",
main), NULL))
plota.lines(last(data, 90), col = "blue")
for (i in 1:n.match) {
plota.lines(data[(min.index[i] - n.query + 1):min.index[i]],
col = "red")
}
text(index4xts(data)[min.index - n.query/2], reference[min.index -
n.query/2], 1:n.match, adj = c(1, -1), col = "black",
xpd = TRUE)
plota.legend(paste("Pattern: ", main, ",Match Number"),
"blue,red")
}
return(list(min.index = min.index, dist = dist[min.index],
query = query, reference = reference, dates = index(data),
main = main))
}
<bytecode: 0x000000e7e11c8a00>
<environment: namespace:SIT>
I tried calling the function using backports package
library(backports)
.onLoad <- function(libname, pkgname) {
backports::import(SIT, "bt.matching.find", force = TRUE)
}
But this also didn't work
Why is R not able to access the function? could this be because this package was built under an older version?
Additional information
Environment
sessionInfo()
R version 3.5.3 (2019-03-11)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 8.1 x64 (build 9600)

Answer 1

The problem was solved with help from the developer of the package, for anyone who is interested in using the code, here are the adjustments that should be done
library(SIT)
library(quantmod)
tickers = 'SPY'
data = getSymbols(tickers, src = 'yahoo', from = '1950-01-01', auto.assign = F)
obj = SIT:::bt.matching.find(Cl(data), normalize.fn = SIT:::normalize.mean, dist.fn = 'dist.euclidean', plot=T)
matches = SIT:::bt.matching.overlay(obj, plot.index=1:90, plot=T)
layout(1:2)
matches = SIT:::bt.matching.overlay(obj, plot=T, layout=T)
SIT:::bt.matching.overlay.table(obj, matches, plot=T, layout=T)