## The RigidODE problem

library(deSolve)

rigidode <- function(t, y, parms) {
  dy1 <- -2  * y[2] * y[3]
  dy2 <- 1.25* y[1] * y[3]
  dy3 <- -0.5* y[1] * y[2]
  list(c(dy1, dy2, dy3))
}
yini  <- c(1, 0, 0.9)
times <- seq(from = 0, to = 20, by = 0.01)
out   <- ode (times = times, y = yini, func = rigidode, parms = NULL)
head (out, n = 3)

plot(out)

library(scatterplot3d)
par(mar = c(0, 0, 0, 0))
scatterplot3d(out[,-1], type = "l", lwd = 2, xlab = "",
              ylab = "", zlab = "", main = "rigidode")