Initial data commit

Task/Matrix-exponentiation-operator/Go/matrix-exponentiation-operator.go

@@ -0,0 +1,71 @@
+package main
+
+import "fmt"
+
+type vector = []float64
+type matrix []vector
+
+func (m1 matrix) mul(m2 matrix) matrix {
+    rows1, cols1 := len(m1), len(m1[0])
+    rows2, cols2 := len(m2), len(m2[0])
+    if cols1 != rows2 {
+        panic("Matrices cannot be multiplied.")
+    }
+    result := make(matrix, rows1)
+    for i := 0; i < rows1; i++ {
+        result[i] = make(vector, cols2)
+        for j := 0; j < cols2; j++ {
+            for k := 0; k < rows2; k++ {
+                result[i][j] += m1[i][k] * m2[k][j]
+            }
+        }
+    }
+    return result
+}
+
+func identityMatrix(n int) matrix {
+    if n < 1 {
+        panic("Size of identity matrix can't be less than 1")
+    }
+    ident := make(matrix, n)
+    for i := 0; i < n; i++ {
+        ident[i] = make(vector, n)
+        ident[i][i] = 1
+    }
+    return ident
+}
+
+func (m matrix) pow(n int) matrix {
+    le := len(m)
+    if le != len(m[0]) {
+        panic("Not a square matrix")
+    }
+    switch {
+    case n < 0:
+        panic("Negative exponents not supported")
+    case n == 0:
+        return identityMatrix(le)
+    case n == 1:
+        return m
+    }
+    pow := identityMatrix(le)
+    base := m
+    e := n
+    for e > 0 {
+        if (e & 1) == 1 {
+            pow = pow.mul(base)
+        }
+        e >>= 1
+        base = base.mul(base)
+    }
+    return pow
+}
+
+func main() {
+    m := matrix{{3, 2}, {2, 1}}
+    for i := 0; i <= 10; i++ {
+        fmt.Println("** Power of", i, "**")
+        fmt.Println(m.pow(i))
+        fmt.Println()
+    }
+}