rxTest({
  ## https://cran.r-project.org/web/packages/diffEq/vignettes/ODEinR.pdf p15

  Vtpol <- rxode2("
d/dt(y) = dy
d/dt(dy) = mu*(1-y^2)*dy - y
## Initial conditions
y(0) = 2
dy(0) = 0
## mu
mu = 1 ## nonstiff; 10 moderately stiff; 1000 stiff
")


  Vtpol2 <- rxode2("
d/dt(y)  = dy
d/dt(dy) = mu*(1-y^2)*dy - y
## Jacobian
df(y)/dy(dy)  = 1
df(dy)/dy(y)  = -2*dy*mu*y - 1
df(dy)/dy(dy) = mu*(1-y^2)
## Initial conditions
y(0) = 2
dy(0) = 0
## mu
mu = 1 ## nonstiff; 10 moderately stiff; 1000 stiff
")

  et <- eventTable()
  et$add.sampling(seq(0, 30, by = 0.01))

  stiff <- solve(Vtpol, et)

  ## plot(stiff$time,stiff$y,type="l")
  counts <- data.frame(stiff$counts, mu = 1, digest = digest::digest(round(as.data.frame(stiff), 3)))

  for (i in 10^(1:7)) {
    stiff$mu <- i
    ## plot(stiff$time,stiff$y,type="l");
    ## title(sprintf("mu=%s",i));
    counts <- rbind(counts, data.frame(stiff$counts, mu = i, digest = digest::digest(round(as.data.frame(stiff), 3))))
  }

  test_that("No User jacobian are called.", {
    expect_true(all(counts$jac == 0))
  })

  ## Data sets match

  ## Changes based on platform.

  ## test_that("Solving of stiff systems by automatic jacobians is expected",{
  ##     expect_equal(digest(counts),"982ce8816e9e1f5db6ee315c71b6a7dc")
  ## })

  counts0 <- counts

  stiff <- solve(Vtpol2, et)
  ## plot(stiff$time,stiff$y,type="l")
  counts <- data.frame(stiff$counts, mu = 1, digest = digest::digest(round(as.data.frame(stiff), 3)))

  for (i in 10^(1:7)) {
    stiff$mu <- i
    ## plot(stiff$time,stiff$y,type="l");
    ## title(sprintf("mu=%s",i));
    counts <- rbind(counts, data.frame(stiff$counts, mu = i, digest = digest::digest(round(as.data.frame(stiff), 3))))
  }

  ## print(counts)

  ## changes based on platform.

  ## test_that("Some User jacobian are called.",{
  ##     expect_true(!all(counts$user_jac == 0))
  ## })

  test_that("Same solutions", {
    expect_true(all(counts0$digest == counts$digest))
  })
})