SAX for Key Recognition

data <- read.delim("data.txt", header = FALSE, sep = "\t")

n <- nrow(data)

minX <- min(data$V2)
maxX <- max(data$V2)
minY <- min(data$V1)
maxY <- max(data$V1)

plot(0, xlim = c(minX, maxX), ylim = c(minY, maxY))

lines(x = data$V2, y = data$V1)

xx <- lowess(data$V1[11:50], f = 0.05)
plot(xx$y, type = "l")

result <- seewave::SAX(
  xx$y,
  alphabet_size = 5,
  PAA_number = 8,
  breakpoints = seq(170, 200, 10)
)

match(result, letters)

## [1] 4 3 3 4 3 2 5 5