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# simple foreach example that plots the sinc function
library(foreach)
# Define the coordinate grid to use
x <- seq(-10, 10, by=0.1)
# Compute starting indices for each task
nw <- getDoParWorkers()
cat(sprintf('Running with %d worker(s)\n', nw))
n <- ceiling(length(x) / nw)
ind <- seq(by=n, length=nw)
# Compute the value of the sinc function at each point in the grid
z <- foreach(i=ind, .combine=cbind) %dopar% {
j <- min(i + n - 1, length(x))
d <- expand.grid(x=x, y=x[i:j])
r <- sqrt(d$x^2 + d$y^2)
matrix(10 * sin(r) / r, length(x))
}
# Plot the results as a perspective plot
persp(x, x, z, ylab='y', theta=30, phi=30, expand=0.5, col="lightblue")
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