Data commit

Task/Determinant-and-permanent/Visual-Basic-.NET/determinant-and-permanent.vb

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+Module Module1
+
+    Function Minor(a As Double(,), x As Integer, y As Integer) As Double(,)
+        Dim length = a.GetLength(0) - 1
+        Dim result(length - 1, length - 1) As Double
+        For i = 1 To length
+            For j = 1 To length
+                If i < x AndAlso j < y Then
+                    result(i - 1, j - 1) = a(i - 1, j - 1)
+                ElseIf i >= x AndAlso j < y Then
+                    result(i - 1, j - 1) = a(i, j - 1)
+                ElseIf i < x AndAlso j >= y Then
+                    result(i - 1, j - 1) = a(i - 1, j)
+                Else
+                    result(i - 1, j - 1) = a(i, j)
+                End If
+            Next
+        Next
+        Return result
+    End Function
+
+    Function Det(a As Double(,)) As Double
+        If a.GetLength(0) = 1 Then
+            Return a(0, 0)
+        Else
+            Dim sign = 1
+            Dim sum = 0.0
+            For i = 1 To a.GetLength(0)
+                sum += sign * a(0, i - 1) * Det(Minor(a, 0, i))
+                sign *= -1
+            Next
+            Return sum
+        End If
+    End Function
+
+    Function Perm(a As Double(,)) As Double
+        If a.GetLength(0) = 1 Then
+            Return a(0, 0)
+        Else
+            Dim sum = 0.0
+            For i = 1 To a.GetLength(0)
+                sum += a(0, i - 1) * Perm(Minor(a, 0, i))
+            Next
+            Return sum
+        End If
+    End Function
+
+    Sub WriteLine(a As Double(,))
+        For i = 1 To a.GetLength(0)
+            Console.Write("[")
+            For j = 1 To a.GetLength(1)
+                If j > 1 Then
+                    Console.Write(", ")
+                End If
+                Console.Write(a(i - 1, j - 1))
+            Next
+            Console.WriteLine("]")
+        Next
+    End Sub
+
+    Sub Test(a As Double(,))
+        If a.GetLength(0) <> a.GetLength(1) Then
+            Throw New ArgumentException("The dimensions must be equal")
+        End If
+
+        WriteLine(a)
+        Console.WriteLine("Permanant  : {0}", Perm(a))
+        Console.WriteLine("Determinant: {0}", Det(a))
+        Console.WriteLine()
+    End Sub
+
+    Sub Main()
+        Test({{1, 2}, {3, 4}})
+        Test({{1, 2, 3, 4}, {4, 5, 6, 7}, {7, 8, 9, 10}, {10, 11, 12, 13}})
+        Test({{0, 1, 2, 3, 4}, {5, 6, 7, 8, 9}, {10, 11, 12, 13, 14}, {15, 16, 17, 18, 19}, {20, 21, 22, 23, 24}})
+    End Sub
+
+End Module