## ----include = FALSE----------------------------------------------------------
knitr::opts_chunk$set(collapse = TRUE, comment = "#>",
                      fig.width = 7, fig.height = 4.2)

## ----setup, message = FALSE---------------------------------------------------
library(shewhartr)
library(ggplot2)
library(dplyr)

## -----------------------------------------------------------------------------
# Correlated baseline — temperature and pressure track together
set.seed(2026)
n     <- 80
Sigma <- matrix(c(1, 0.92, 0.92, 1), 2, 2)
Z     <- MASS::mvrnorm(n, mu = c(0, 0), Sigma = Sigma)

# A "stuck pressure" fault: temperature still varies, pressure stays put
faulty <- cbind(temp = rnorm(20, 0, 1), pressure = rnorm(20, 0, 0.05))

reactor <- tibble::tibble(
  hour     = 1:100,
  temp     = c(Z[, 1], faulty[, 1]),
  pressure = c(Z[, 2], faulty[, 2])
)

## -----------------------------------------------------------------------------
shewhart_i_mr(reactor, value = temp,     index = hour) |> autoplot()
shewhart_i_mr(reactor, value = pressure, index = hour) |> autoplot()

## -----------------------------------------------------------------------------
fit <- shewhart_hotelling(reactor, vars = c(temp, pressure),
                          index = hour)
fit
autoplot(fit)

## -----------------------------------------------------------------------------
fit$augmented |>
  filter(.flag_signal) |>
  select(hour, .t2, .upper, starts_with(".contrib_")) |>
  head(5)

## -----------------------------------------------------------------------------
set.seed(7)
in_control <- as.data.frame(MASS::mvrnorm(120, c(0, 0), Sigma))
names(in_control) <- c("temp", "pressure")
calib <- calibrate(in_control, vars = c(temp, pressure),
                   chart = "hotelling")

# Fresh data — pressure-sensor fault for the last 10 readings
new_data <- as.data.frame(MASS::mvrnorm(40, c(0, 0), Sigma))
names(new_data) <- c("temp", "pressure")
new_data$pressure[31:40] <- rnorm(10, 0, 0.05)

mon <- monitor(new_data, calib)
sum(mon$augmented$.flag_signal)
autoplot(mon)