Data commit

Task/Polynomial-regression/Go/polynomial-regression-1.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"gonum.org/v1/gonum/mat"
+)
+
+func main() {
+	var (
+		x = []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
+		y = []float64{1, 6, 17, 34, 57, 86, 121, 162, 209, 262, 321}
+
+		degree = 2
+
+		a = Vandermonde(x, degree+1)
+		b = mat.NewDense(len(y), 1, y)
+		c = mat.NewDense(degree+1, 1, nil)
+	)
+
+	var qr mat.QR
+	qr.Factorize(a)
+
+	const trans = false
+	err := qr.SolveTo(c, trans, b)
+	if err != nil {
+		log.Fatalf("could not solve QR: %+v", err)
+	}
+	fmt.Printf("%.3f\n", mat.Formatted(c))
+}
+
+func Vandermonde(a []float64, d int) *mat.Dense {
+	x := mat.NewDense(len(a), d, nil)
+	for i := range a {
+		for j, p := 0, 1.0; j < d; j, p = j+1, p*a[i] {
+			x.Set(i, j, p)
+		}
+	}
+	return x
+}

Task/Polynomial-regression/Go/polynomial-regression-2.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+    "fmt"
+
+    "github.com/skelterjohn/go.matrix"
+)
+
+var xGiven = []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
+var yGiven = []float64{1, 6, 17, 34, 57, 86, 121, 162, 209, 262, 321}
+var degree = 2
+
+func main() {
+    m := len(yGiven)
+    n := degree + 1
+    y := matrix.MakeDenseMatrix(yGiven, m, 1)
+    x := matrix.Zeros(m, n)
+    for i := 0; i < m; i++ {
+        ip := float64(1)
+        for j := 0; j < n; j++ {
+            x.Set(i, j, ip)
+            ip *= xGiven[i]
+        }
+    }
+
+    q, r := x.QR()
+    qty, err := q.Transpose().Times(y)
+    if err != nil {
+        fmt.Println(err)
+        return
+    }
+    c := make([]float64, n)
+    for i := n - 1; i >= 0; i-- {
+        c[i] = qty.Get(i, 0)
+        for j := i + 1; j < n; j++ {
+            c[i] -= c[j] * r.Get(i, j)
+        }
+        c[i] /= r.Get(i, i)
+    }
+    fmt.Println(c)
+}