From 9bdd65701843345effb5d6a197dd8b43617cdd90 Mon Sep 17 00:00:00 2001
From: Ishan Jain <contact@ishanjain.me>
Date: Mon, 29 May 2023 00:47:07 +0530
Subject: [PATCH] Initial commit, Added example of stratified sampling

---
 .gitignore  |  1 +
 Cargo.lock  | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml  |  7 +++++
 src/main.rs | 35 ++++++++++++++++++++++
 4 files changed, 128 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Cargo.lock
 create mode 100644 Cargo.toml
 create mode 100644 src/main.rs

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..eed3a4c
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,85 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "getrandom"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.107"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fbe5e23404da5b4f555ef85ebed98fb4083e55a00c317800bc2a50ede9f3d219"
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed0cfbc8191465bed66e1718596ee0b0b35d5ee1f41c5df2189d0fe8bde535ba"
+
+[[package]]
+name = "rand"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+ "rand_hc",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "rand_hc"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d51e9f596de227fda2ea6c84607f5558e196eeaf43c986b724ba4fb8fdf497e7"
+dependencies = [
+ "rand_core",
+]
+
+[[package]]
+name = "raytracing-the-rest-of-your-life"
+version = "0.1.0"
+dependencies = [
+ "rand",
+]
+
+[[package]]
+name = "wasi"
+version = "0.10.2+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..4ef7614
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "raytracing-the-rest-of-your-life"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+rand = "0.8.4"
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..41689f3
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,35 @@
+use rand::Rng;
+
+fn main() {
+    let mut inside_circle = 0u64;
+    let mut inside_circle_stratified = 0u64;
+    let mut rng = rand::thread_rng();
+
+    const SQRT_N: u64 = 10000;
+
+    for i in 0..SQRT_N {
+        for j in 0..SQRT_N {
+            let mut x: f64 = rng.gen_range(-1.0..=1.0);
+            let mut y: f64 = rng.gen_range(-1.0..=1.0);
+
+            if x * x + y * y < 1.0 {
+                inside_circle += 1;
+            }
+
+            x = (2.0f64 * (i as f64 + rng.gen::<f64>()) / SQRT_N as f64) - 1.0;
+            y = (2.0f64 * (j as f64 + rng.gen::<f64>()) / SQRT_N as f64) - 1.0;
+
+            if x * x + y * y < 1.0 {
+                inside_circle_stratified += 1;
+            }
+        }
+    }
+
+    let n = SQRT_N as f64 * SQRT_N as f64;
+
+    println!(
+        "regular estimation = {} stratified estimate = {}",
+        4.0 * inside_circle as f64 / n,
+        4.0 * inside_circle_stratified as f64 / n
+    );
+}