From 8c8e2e08d2ae89ba18ca05bab446e4642798dce2 Mon Sep 17 00:00:00 2001
From: Jules Laplace <julescarbon@gmail.com>
Date: Tue, 5 Jun 2018 23:56:12 +0200
Subject: pulling in wav2pix code

---
 app/client/util/math.js | 52 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 app/client/util/math.js

(limited to 'app/client/util/math.js')

diff --git a/app/client/util/math.js b/app/client/util/math.js
new file mode 100644
index 0000000..253bacd
--- /dev/null
+++ b/app/client/util/math.js
@@ -0,0 +1,52 @@
+export function mod(n,m){ return n-(m * Math.floor(n/m)) }
+export function clamp(n,a,b) { return n<a?a:n<b?n:b }
+export function norm(n,a,b) { return (n-a) / (b-a) }
+export function lerp(n,a,b) { return (b-a)*n+a }
+export function mix(n,a,b) { return a*(1-n)+b*n }
+export function randint(n) { return Math.floor(Math.random()*n) }
+export function randrange(a,b){ return Math.random() * (b-a) + a }
+export function randsign(){ return Math.random() >= 0.5 ? -1 : 1 }
+export function choice (a){ return a[ Math.floor(Math.random() * a.length) ] }
+export function lerp(n,a,b){ return (b-a)*n+a }
+export function angle(x0,y0,x1,y1){ return Math.atan2(y1-y0,x1-x0) }
+export function dist(x0,y0,x1,y1){ return Math.sqrt(Math.pow(x1-x0,2)+Math.pow(y1-y0,2)) }
+export function xor(a,b){ a=!!a; b=!!b; return (a||b) && !(a&&b) }
+export function quantize(a,b){ return Math.floor(a/b)*b }
+export function shuffle(a){
+  for (var i = a.length; i > 0; i--){
+    var r = randint(i)
+    var swap = a[i-1]
+    a[i-1] = a[r]
+    a[r] = swap
+  }
+  return a
+}
+// returns a gaussian random function with the given mean and stdev.
+export function gaussian(mean, stdev) {
+  let y2;
+  let use_last = false;
+  return () => {
+    let y1;
+    if (use_last) {
+      y1 = y2;
+      use_last = false;
+    }
+    else {
+      let x1, x2, w;
+      do {
+        x1 = 2.0 * Math.random() - 1.0;
+        x2 = 2.0 * Math.random() - 1.0;
+        w  = x1 * x1 + x2 * x2;               
+      } while( w >= 1.0);
+      w = Math.sqrt((-2.0 * Math.log(w))/w);
+      y1 = x1 * w;
+      y2 = x2 * w;
+      use_last = true;
+    }
+
+    let retval = mean + stdev * y1;
+    if (retval > 0) 
+      return retval;
+    return -retval;
+  }
+}
-- 
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