From 5edefe38d2dc632f61ba31a1c001f9c90fefb58b Mon Sep 17 00:00:00 2001
From: Dan Buch <daniel.buch@gmail.com>
Date: Sat, 25 Aug 2012 21:48:12 -0400
Subject: [PATCH] A crappy implementation of Newton's method for finding square
 root

---
 gotime/src/exercise-sqrt.go | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 gotime/src/exercise-sqrt.go

diff --git a/gotime/src/exercise-sqrt.go b/gotime/src/exercise-sqrt.go
new file mode 100644
index 0000000..806c350
--- /dev/null
+++ b/gotime/src/exercise-sqrt.go
@@ -0,0 +1,25 @@
+package main
+
+import (
+    "fmt"
+    "math"
+)
+
+// using Newton's method
+func Sqrt(x float64) float64 {
+    z := x - (x * 0.1)
+    for i := 0 ; i < 1000 ; i++ {
+        newZ := z - (((z * z) - x) / 2 * z)
+        diff := math.Abs(newZ) - math.Abs(z)
+        if math.Abs(diff) < 0.01 {
+            return newZ
+        }
+        z = newZ
+    }
+    return z
+}
+
+func main() {
+    fmt.Printf("stdlib -> %f\n", math.Sqrt(2))
+    fmt.Printf("newton -> %f\n", Sqrt(2))
+}