June 2018 Update

Task/Element-wise-operations/C-sharp/element-wise-operations.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+public static class ElementWiseOperations
+{
+    private static readonly Dictionary<string, Func<double, double, double>> operations =
+        new Dictionary<string, Func<double, double, double>> {
+            { "add", (a, b) => a + b },
+            { "sub", (a, b) => a - b },
+            { "mul", (a, b) => a * b },
+            { "div", (a, b) => a / b },
+            { "pow", (a, b) => Math.Pow(a, b) }
+        };
+
+    private static readonly Func<double, double, double> nothing = (a, b) => a;
+
+    public static double[,] DoOperation(this double[,] m, string name, double[,] other) =>
+        DoOperation(m, operations.TryGetValue(name, out var operation) ? operation : nothing, other);
+
+    public static double[,] DoOperation(this double[,] m, Func<double, double, double> operation, double[,] other) {
+        if (m == null || other == null) throw new ArgumentNullException();
+        int rows = m.GetLength(0), columns = m.GetLength(1);
+        if (rows != other.GetLength(0) || columns != other.GetLength(1)) {
+            throw new ArgumentException("Matrices have different dimensions.");
+        }
+
+        double[,] result = new double[rows, columns];
+        for (int r = 0; r < rows; r++) {
+            for (int c = 0; c < columns; c++) {
+                result[r, c] = operation(m[r, c], other[r, c]);
+            }
+        }
+        return result;
+    }
+
+    public static double[,] DoOperation(this double[,] m, string name, double number) =>
+        DoOperation(m, operations.TryGetValue(name, out var operation) ? operation : nothing, number);
+
+    public static double[,] DoOperation(this double[,] m, Func<double, double, double> operation, double number) {
+        if (m == null) throw new ArgumentNullException();
+        int rows = m.GetLength(0), columns = m.GetLength(1);
+        double[,] result = new double[rows, columns];
+        for (int r = 0; r < rows; r++) {
+            for (int c = 0; c < columns; c++) {
+                result[r, c] = operation(m[r, c], number);
+            }
+        }
+        return result;
+    }
+
+    public static void Print(this double[,] m) {
+        if (m == null) throw new ArgumentNullException();
+        int rows = m.GetLength(0), columns = m.GetLength(1);
+        for (int r = 0; r < rows; r++) {
+            Console.WriteLine("[ " + string.Join(", ", Enumerable.Range(0, columns).Select(c => m[r, c])) + " ]");
+        }
+    }
+
+}
+
+public class Program
+{
+    public static void Main() {
+        double[,] matrix = {
+            { 1, 2, 3, 4 },
+            { 5, 6, 7, 8 },
+            { 9, 10, 11, 12 }
+        };
+
+        double[,] tens = {
+            { 10, 10, 10, 10 },
+            { 20, 20, 20, 20 },
+            { 30, 30, 30, 30 }
+        };
+
+        matrix.Print();
+        WriteLine();
+
+        (matrix = matrix.DoOperation("add", tens)).Print();
+        WriteLine();
+
+        matrix.DoOperation((a, b) => b - a, 100).Print();
+    }
+}