R Under development (unstable) (2025-06-05 r88281 ucrt) -- "Unsuffered Consequences"
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Platform: x86_64-w64-mingw32/x64

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> source("incl/start.R")
Loading required package: parallelly
Loading required package: future
> 
> plan(batchtools_local)
> 
> ## CRAN processing times:
> ## On Windows 32-bit, don't run these tests via batchtools
> if (!fullTest && isWin32) plan(sequential)
> 
> options(future.demo.mandelbrot.nrow = 2L)
> options(future.demo.mandelbrot.resolution = 50L)
> options(future.demo.mandelbrot.delay = FALSE)
> 
> message("*** Demos ...")
*** Demos ...
> 
> message("*** Mandelbrot demo of the 'future' package ...")
*** Mandelbrot demo of the 'future' package ...
> 
> demo("mandelbrot", package = "future", ask = FALSE)


	demo(mandelbrot)
	---- ~~~~~~~~~~

> library(future)

> library(graphics)

> plot_what_is_done <- function(counts) {
+   for (kk in seq_along(counts)) {
+     f <- counts[[kk]]
+ 
+     ## Already plotted?
+     if (!inherits(f, "Future")) next
+ 
+     ## Not resolved?
+     if (!resolved(f)) next
+ 
+     message(sprintf("Plotting tile #%d of %d ...", kk, n))
+     counts[[kk]] <- value(f)
+     screen(kk)
+     plot(counts[[kk]])
+   }
+ 
+   counts
+ }

> ## Options
> region <- getOption("future.demo.mandelbrot.region", 1L)

> if (!is.list(region)) {
+   if (region == 1L) {
+     region <- list(xmid = -0.75, ymid = 0.0, side = 3.0)
+   } else if (region == 2L) {
+     region <- list(xmid = 0.283, ymid = -0.0095, side = 0.00026)
+   } else if (region == 3L) {
+     region <- list(xmid = 0.282989, ymid = -0.01, side = 3e-8)
+   }
+ }

> nrow <- getOption("future.demo.mandelbrot.nrow", 3L)

> resolution <- getOption("future.demo.mandelbrot.resolution", 400L)

> delay <- getOption("future.demo.mandelbrot.delay", interactive())

> if (isTRUE(delay)) {
+   delay <- function(counts) Sys.sleep(1.0)
+ } else if (!is.function(delay)) {
+   delay <- function(counts) {}
+ }

> ## Generate Mandelbrot tiles to be computed
> Cs <- mandelbrot_tiles(xmid = region$xmid, ymid = region$ymid,
+                        side = region$side, nrow = nrow,
+                        resolution = resolution)

> if (interactive()) {
+   dev.new()
+   plot.new()
+   split.screen(dim(Cs))
+   for (ii in seq_along(Cs)) {
+     screen(ii)
+     par(mar = c(0, 0, 0, 0))
+     text(x = 1 / 2, y = 1 / 2, sprintf("Future #%d\nunresolved", ii), cex = 2)
+   }
+ } else {
+   split.screen(dim(Cs))
+ }
[1] 1 2 3 4

> ## Create all Mandelbrot tiles via lazy futures
> n <- length(Cs)

> message(sprintf("Creating %d Mandelbrot tiles:", n), appendLF = FALSE)
Creating 4 Mandelbrot tiles:
> counts <- lapply(seq_along(Cs), FUN=function(ii) {
+   message(" ", ii, appendLF = FALSE)
+   C <- Cs[[ii]]
+   future({
+     message(sprintf("Calculating tile #%d of %d ...", ii, n), appendLF = FALSE)
+     fit <- mandelbrot(C)
+ 
+     ## Emulate slowness
+     delay(fit)
+ 
+     message(" done")
+     fit
+   }, lazy = TRUE)
+ })
 1 2 3 4
> message(".")
.

> ## Calculate and plot tiles
> repeat {
+   counts <- plot_what_is_done(counts)
+   if (!any(sapply(counts, FUN = inherits, "Future"))) break
+ }
[04:37:47.758] Attaching 1 packages ('future') ...
[04:37:47.766] Attaching 1 packages ('future') ... done
[04:37:49.080] Launched future #1
Plotting tile #1 of 4 ...
Calculating tile #1 of 4 ... done
[04:37:49.519] Attaching 1 packages ('future') ...
[04:37:49.533] Attaching 1 packages ('future') ... done
[04:37:50.862] Launched future #1
Plotting tile #2 of 4 ...
Calculating tile #2 of 4 ... done
[04:37:50.982] Attaching 1 packages ('future') ...
[04:37:50.993] Attaching 1 packages ('future') ... done
[04:37:52.318] Launched future #1
Plotting tile #3 of 4 ...
Calculating tile #3 of 4 ... done
[04:37:52.464] Attaching 1 packages ('future') ...
[04:37:52.478] Attaching 1 packages ('future') ... done
[04:37:53.710] Launched future #1
Plotting tile #4 of 4 ...
Calculating tile #4 of 4 ... done

> close.screen()
[1] 1 2 3 4

> message("SUGGESTION: Try to rerun this demo after changing strategy for how futures are resolved, e.g. plan(multisession).\n")
SUGGESTION: Try to rerun this demo after changing strategy for how futures are resolved, e.g. plan(multisession).

> 
> message("*** Demos ... DONE")
*** Demos ... DONE
> 
> source("incl/end.R")
> 
> proc.time()
   user  system elapsed 
   2.17    0.53    7.76