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Animate a Multi-objective Optimization Plot

Source: R/plotting.R
animate_mobo2.Rd

Renders generateMoboPlot2() one iteration at a time and encodes the frames into a video, so a talk or a supplement can show an optimisation run building up rather than only its end state. Frame i is the same plot restricted to the data up to iteration i: the mean points, their bootstrapped intervals, the fitted line and its equation all move as the run proceeds.

Usage

animate_mobo2(
  data,
  x = "Iteration",
  y,
  filename,
  ...,
  fps = 5,
  end_pause = 2,
  width = 8,
  height = 5,
  dpi = 150,
  label_iterations = TRUE
)

Arguments

data

A data frame holding the run, as for generateMoboPlot2().

x

A string naming the iteration column in data. Default "Iteration".

y

A string naming the objective column in data.

filename

Path of the video to write. Its extension chooses the container: .mp4, .gif, .mov, .webm – whatever the av package's FFmpeg build can encode.

...

Further arguments for generateMoboPlot2(), e.g. phaseCol, fillColourGroup, ytext, legendPos, fillLabels.

fps

Frames per second. One frame is drawn per iteration, so this is equally the number of iterations shown per second. Default 5.

end_pause

Seconds to hold the final frame, so the finished plot can be read before the video ends or loops. Default 2; use 0 for no hold.

width, height

Frame size in inches. Default 8 x 5.

dpi

Resolution. Default 150, so the default frame is 1200 x 750 px.

label_iterations

Whether to caption each frame with the iteration it shows. Default TRUE, which writes the plot's subtitle.

Value

Invisibly returns filename.

Details

The plot is built once from the complete data, and a frame only ever hides rows. That is what keeps the axes, the sampling/optimisation guides and the legend still while the data grows – and it is also the only way the early frames can be drawn at all, since generateMoboPlot2() requires both phases to be present and the first iterations are all sampling.

See also

generateMoboPlot2() for the static plot.

Examples

# \donttest{
# Kept deliberately tiny: every frame is a full ggplot render, so the cost
# of the example is set by the number of iterations, not by the frame size.
if (requireNamespace("av", quietly = TRUE)) {
  set.seed(42)
  df <- data.frame(
    Iteration   = rep(1:3, each = 4),
    ConditionID = rep(rep(c("A", "B"), each = 2), 3),
    Phase       = rep(c("Sampling", "Optimization"), times = c(2 * 4, 4))
  )
  df$score <- 0.3 + 0.05 * df$Iteration + stats::rnorm(nrow(df), sd = 0.05)

  animate_mobo2(
    df,
    y = "score", ytext = "Score",
    filename = file.path(tempdir(), "mobo.mp4"),
    width = 4, height = 2.5, dpi = 96, end_pause = 0
  )
}
#> Rendering 3 frames ...
#> Saved animation to '/tmp/Rtmp2Ft8yp/mobo.mp4' (3 iterations at 5 fps, 384 x 240 px).
# }