September 2017 Update

Task/Matrix-arithmetic/Go/matrix-arithmetic-2.go

@@ -0,0 +1,44 @@
+package main
+
+import "fmt"
+
+func main() {
+    fmt.Println(ryser([][]float64{
+        {1, 2},
+        {3, 4}}))
+    fmt.Println(ryser([][]float64{
+        {2, 9, 4},
+        {7, 5, 3},
+        {6, 1, 8}}))
+}
+
+func ryser(m [][]float64) (d float64) {
+    gray := 0
+    csum := make([]float64, len(m))
+    sgn := float64(len(m)&1<<1 - 1)
+    n2 := uint32(1) << uint(len(m))
+    for i := uint32(1); i < n2; i++ {
+        r := [...]byte{
+            0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
+            31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9,
+        }[i&-i*0x077CB531>>27]
+        b := 1 << r
+        if gray&b == 0 {
+            for c, e := range m[r] {
+                csum[c] += e
+            }
+        } else {
+            for c, e := range m[r] {
+                csum[c] -= e
+            }
+        }
+        gray ^= b
+        p := sgn
+        for _, e := range csum {
+            p *= e
+        }
+        d += p
+        sgn = -sgn
+    }
+    return
+}

Task/Matrix-arithmetic/Go/matrix-arithmetic-3.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+    "fmt"
+
+    "github.com/skelterjohn/go.matrix"
+)
+
+func main() {
+    fmt.Println(matrix.MakeDenseMatrixStacked([][]float64{
+        {1, 2},
+        {3, 4}}).Det())
+    fmt.Println(matrix.MakeDenseMatrixStacked([][]float64{
+        {2, 9, 4},
+        {7, 5, 3},
+        {6, 1, 8}}).Det())
+}

Task/Matrix-arithmetic/Go/matrix-arithmetic-4.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+    "fmt"
+
+    "github.com/gonum/matrix/mat64"
+)
+
+func main() {
+    fmt.Println(mat64.Det(mat64.NewDense(2, 2, []float64{
+        1, 2,
+        3, 4})))
+    fmt.Println(mat64.Det(mat64.NewDense(3, 3, []float64{
+        2, 9, 4,
+        7, 5, 3,
+        6, 1, 8})))
+}