add the thomas algorithm in go (#405)

* add the thomas algorithm in go

* change the name golang to go

Author: Julian

contents/thomas_algorithm/code/golang/thomas.go

@@ -0,0 +1,37 @@
+package main
+
+import "fmt"
+
+func thomas(a, b, c, d []float64) []float64 {
+	c[0] = c[0] / b[0]
+	d[0] = d[0] / b[0]
+
+	for i := 1; i < len(d); i++ {
+		scale := 1. / (b[i] - c[i-1]*a[i])
+		c[i] *= scale
+		d[i] = (d[i] - a[i]*d[i-1]) * scale
+	}
+
+	for i := len(d) - 2; i >= 0; i-- {
+		d[i] -= c[i] * d[i+1]
+	}
+
+	return d
+}
+
+func main() {
+	a := []float64{0., 2., 3.}
+	b := []float64{1., 3., 6.}
+	c := []float64{4., 5., 0.}
+	d := []float64{7., 5., 3.}
+
+	fmt.Println("The system,")
+	fmt.Println("[1.0  4.0  0.0][x] = [7.0]")
+	fmt.Println("[2.0  3.0  5.0][y] = [5.0]")
+	fmt.Println("[0.0  3.0  6.0][z] = [3.0]")
+	fmt.Println("has the solution:")
+	solve := thomas(a, b, c, d)
+	for _, i := range solve {
+		fmt.Printf("[%f]\n", i)
+	}
+}

contents/thomas_algorithm/thomas_algorithm.md

@@ -111,6 +111,8 @@ You will find this algorithm implemented [in this project](https://scratch.mit.e
 [import, lang:"java"](code/java/thomas.java)
 {% sample lang="hs" %}
 [import, lang:"haskell"](code/haskell/thomas.hs)
+{% sample lang="go" %}
+[import, lang:"go"](code/golang/thomas.go)
 {% sample lang="swift" %}
 [import, lang:"swift"](code/swift/thomas.swift)
 {% sample lang="php" %}