From bdd72c150a5f2b45465f4b5b2448296d9368c283 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mos=C3=A8=20Giordano?= <m.giordano@ucl.ac.uk>
Date: Tue, 26 Nov 2024 20:35:09 -0500
Subject: [PATCH] Add Julia implementation using `OhMyThreads.jl`

---
 julia_ohmythreads_pi_dir/.gitignore   |  1 +
 julia_ohmythreads_pi_dir/Project.toml |  6 ++++
 julia_ohmythreads_pi_dir/pi.jl        | 48 +++++++++++++++++++++++++++
 julia_ohmythreads_pi_dir/run.sh       |  7 ++++
 4 files changed, 62 insertions(+)
 create mode 100644 julia_ohmythreads_pi_dir/.gitignore
 create mode 100644 julia_ohmythreads_pi_dir/Project.toml
 create mode 100755 julia_ohmythreads_pi_dir/pi.jl
 create mode 100755 julia_ohmythreads_pi_dir/run.sh

diff --git a/julia_ohmythreads_pi_dir/.gitignore b/julia_ohmythreads_pi_dir/.gitignore
new file mode 100644
index 0000000..ba39cc5
--- /dev/null
+++ b/julia_ohmythreads_pi_dir/.gitignore
@@ -0,0 +1 @@
+Manifest.toml
diff --git a/julia_ohmythreads_pi_dir/Project.toml b/julia_ohmythreads_pi_dir/Project.toml
new file mode 100644
index 0000000..d64665c
--- /dev/null
+++ b/julia_ohmythreads_pi_dir/Project.toml
@@ -0,0 +1,6 @@
+[deps]
+OhMyThreads = "67456a42-1dca-4109-a031-0a68de7e3ad5"
+
+[compat]
+OhMyThreads = "0.7"
+julia = "1.10"
diff --git a/julia_ohmythreads_pi_dir/pi.jl b/julia_ohmythreads_pi_dir/pi.jl
new file mode 100755
index 0000000..4e48121
--- /dev/null
+++ b/julia_ohmythreads_pi_dir/pi.jl
@@ -0,0 +1,48 @@
+#!/usr/bin/env julia
+
+using Pkg
+Pkg.activate(@__DIR__)
+Pkg.resolve()
+Pkg.instantiate()
+
+using Base.Threads: nthreads
+using OhMyThreads: tmapreduce
+
+function _picalc(numsteps)
+    slice = 1 / numsteps
+
+    return tmapreduce(+, 1:numsteps; ntasks=nthreads()) do i
+        4.0 / (1.0 + ((i - 0.5) * slice) ^ 2)
+    end * slice
+end
+
+function picalc(numsteps)
+
+    println("Calculating PI using:")
+    println("  ", numsteps, " slices")
+    println("  ", nthreads(), " thread(s)")
+
+    start = time()
+    mypi = _picalc(numsteps)
+    elapsed = time() - start
+
+    println("Obtained value of PI: ", mypi)
+    println("Time taken: ", round(elapsed; digits=3), " seconds")
+
+end
+
+numsteps = if length(ARGS) > 0
+    parse(Int, ARGS[1])
+else
+    1_000_000_000
+end
+
+# Warm up kernel
+print("  Warming up...")
+warms = time()
+_picalc(10)
+warmt = time() - warms
+println("done. [", round(warmt; digits=3), "s]\n")
+
+# Run the full example
+picalc(numsteps)
diff --git a/julia_ohmythreads_pi_dir/run.sh b/julia_ohmythreads_pi_dir/run.sh
new file mode 100755
index 0000000..b4ca7f9
--- /dev/null
+++ b/julia_ohmythreads_pi_dir/run.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+if [[ -z "${JULIA_NUM_THREADS}" ]]; then
+    export JULIA_NUM_THREADS="${OMP_NUM_THREADS:-1}"
+fi
+
+julia pi.jl "${@}"