## ----setup, include = FALSE---------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE, comment = "#>", message = FALSE, warning = FALSE,
  fig.width = 7, fig.height = 4.2, dpi = 150, fig.align = "center"
)
set.seed(1)

## -----------------------------------------------------------------------------
library(mixqr)

## ----fit----------------------------------------------------------------------
fit <- mixqr(equivalence ~ nox, data = engine, tau = 0.5, m = 2,
             variance = "stochEM")
fit

## ----summary------------------------------------------------------------------
summary(fit)

## ----plot, fig.alt = "Engine data coloured by recovered regime with two median regression lines."----
library(ggplot2)

dat <- transform(engine, regime = factor(predict(fit, type = "class")))
grid <- data.frame(nox = seq(min(engine$nox), max(engine$nox), length.out = 100))
lines <- do.call(rbind, lapply(1:2, function(j) {
  data.frame(nox = grid$nox,
             equivalence = cbind(1, grid$nox) %*% fit$beta[, j],
             regime = factor(j))
}))

ggplot(dat, aes(nox, equivalence, colour = regime)) +
  geom_point(size = 2, alpha = 0.8) +
  geom_line(data = lines, linewidth = 1.1) +
  scale_colour_manual(values = c("#1b6ca8", "#e07b39")) +
  labs(x = "Nitrous oxide", y = "Equivalence ratio",
       title = "Two median regimes recovered by mixqr") +
  theme_minimal(base_size = 12)

## ----cite, eval = FALSE-------------------------------------------------------
# citation("mixqr")