From 188313d52087c9c9c34f5fd1fc721c19e78efbdc Mon Sep 17 00:00:00 2001
From: Andrew Johnson <andrewjohnson@Andrews-MacBook-Pro.local>
Date: Wed, 16 May 2018 15:44:47 -0600
Subject: [PATCH] thread 5

---
 Chapter08/Cargo.toml |  6 ++++++
 Chapter08/thread5.rs | 46 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 Chapter08/thread5.rs

diff --git a/Chapter08/Cargo.toml b/Chapter08/Cargo.toml
index d9329cc..122ea44 100644
--- a/Chapter08/Cargo.toml
+++ b/Chapter08/Cargo.toml
@@ -5,6 +5,8 @@ version = "1.0.0"
 [dependencies]
 nix = "0.10"
 thread-id = "3.3"
+lazy_static = "1.0"
+rand = "0.4.2"
 
 [[bin]]
 name = "process_a"
@@ -41,3 +43,7 @@ path = "thread3.rs"
 [[bin]]
 name = "thread4"
 path = "thread4.rs"
+
+[[bin]]
+name = "thread5"
+path = "thread5.rs"
diff --git a/Chapter08/thread5.rs b/Chapter08/thread5.rs
new file mode 100644
index 0000000..3384b02
--- /dev/null
+++ b/Chapter08/thread5.rs
@@ -0,0 +1,46 @@
+use std::{thread,time};
+extern crate rand;
+use std::sync::{Arc,Mutex};
+#[macro_use] extern crate lazy_static;
+
+lazy_static! {
+   static ref NEURAL_NET_WEIGHTS: Vec<Arc<Mutex<Vec<f64>>>> = {
+      let mut nn = Vec::with_capacity(10000);
+      for _ in 0..10000 {
+         let mut mm = Vec::with_capacity(100);
+         for _ in 0..100 {
+            mm.push(rand::random::<f64>());
+         }
+         let mm = Arc::new(Mutex::new(mm));
+         nn.push(mm);
+      }
+      nn
+   };
+}
+
+fn train() {
+   let t = time::Duration::from_millis(100);
+   loop {
+      for _ in 0..100 {
+         let update_position = rand::random::<u64>() % 1000000;
+         let update_column = update_position / 10000;
+         let update_row = update_position % 100;
+         let update_value = rand::random::<f64>();
+         let mut update_column = NEURAL_NET_WEIGHTS[update_column as usize].lock().unwrap();
+         update_column[update_row as usize] = update_value;
+      }
+      thread::sleep(t);
+   }
+}
+
+fn main() {
+   let t = time::Duration::from_millis(1000);
+
+   for _ in 0..500 {
+      thread::spawn(train);
+   }
+
+   loop {
+      thread::sleep(t);
+   }
+}