Kronecker product: Difference between revisions
Added C#
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</pre>
=={{header|C sharp}}==
<lang csharp>using System;
using System.Collections;
using System.Collections.Generic;
using static System.Linq.Enumerable;
public static class KroneckerProduct
{
public static void Main() {
int[,] left = { {1, 2}, {3, 4} };
int[,] right = { {0, 5}, {6, 7} };
Print(Multiply(left, right));
left = new [,] { {0, 1, 0}, {1, 1, 1}, {0, 1, 0} };
right = new [,] { {1, 1, 1, 1}, {1, 0, 0, 1}, {1, 1, 1, 1} };
Print(Multiply(left, right));
}
static int[,] Multiply(int[,] left, int[,] right) {
(int lRows, int lColumns) = (left.GetLength(0), left.GetLength(1));
(int rRows, int rColumns) = (right.GetLength(0), right.GetLength(1));
int[,] result = new int[lRows * rRows, lColumns * rColumns];
foreach (var (r, c) in from r in Range(0, lRows) from c in Range(0, lColumns) select (r, c)) {
Copy(r * rRows, c * rColumns, left[r, c]);
}
return result;
void Copy(int startRow, int startColumn, int multiplier) {
foreach (var (r, c) in from r in Range(0, rRows) from c in Range(0, rColumns) select (r, c)) {
result[startRow + r, startColumn + c] = right[r, c] * multiplier;
}
}
}
static void Print(int[,] matrix) {
(int rows, int columns) = (matrix.GetLength(0), matrix.GetLength(1));
int width = matrix.Cast<int>().Select(LengthOf).Max();
for (int row = 0; row < rows; row++) {
Console.WriteLine("| " + string.Join(" ", Range(0, columns).Select(column => (matrix[row, column] + "").PadLeft(width, ' '))) + " |");
}
Console.WriteLine();
}
private static int LengthOf(int i) {
if (i < 0) return LengthOf(-i) + 1;
int length = 0;
while (i > 0) {
length++;
i /= 10;
}
return length;
}
}</lang>
{{out}}
<pre>
| 0 5 0 10 |
| 6 7 12 14 |
| 0 15 0 20 |
| 18 21 24 28 |
| 0 0 0 0 1 1 1 1 0 0 0 0 |
| 0 0 0 0 1 0 0 1 0 0 0 0 |
| 0 0 0 0 1 1 1 1 0 0 0 0 |
| 1 1 1 1 1 1 1 1 1 1 1 1 |
| 1 0 0 1 1 0 0 1 1 0 0 1 |
| 1 1 1 1 1 1 1 1 1 1 1 1 |
| 0 0 0 0 1 1 1 1 0 0 0 0 |
| 0 0 0 0 1 0 0 1 0 0 0 0 |
| 0 0 0 0 1 1 1 1 0 0 0 0 |</pre>
=={{header|D}}==
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