// Определтиьель
public double Determinant()
{
double det = 0;
int rows = n;
if (rows == 1)
{
return(a[0, 0]);
}
squareMatrix na = new squareMatrix(rows - 1);
for (int j = 0; j < rows; j++)
{
na = SubMatrix(0, j);
if (j % 2 == 0)
{
det += na.Determinant() * a[0, j];
}
else
{
det -= na.Determinant() * a[0, j];
}
}
return(det);
}
//обртная матрица
public squareMatrix Obratnya(squareMatrix m)
{
int rows = n;
squareMatrix res = new squareMatrix(rows);
squareMatrix na = new squareMatrix(rows - 1);
double det = m.Determinant();
if (det == 0)
{
throw new Exception("Матрица вырожденная");
}
int k;
for (int i = 0; i < rows; i++)
{
if (i % 2 == 0)
{
k = 1;
}
else
{
k = -1;
}
for (int j = 0; j < rows; j++)
{
na = m.SubMatrix(i, j);
res[j, i] = k * na.Determinant() / det;
k = -k;
}
}
return(res);
}
// минор n-того порядка
squareMatrix SubMatrix(int i1, int j1)
{
int rows = n;
squareMatrix na = new squareMatrix(rows - 1);
for (int i = 0; i < i1; i++)
{
for (int j = 0; j < j1; j++)
{
na[i, j] = a[i, j];
}
for (int j = j1 + 1; j < rows; j++)
{
na[i, j - 1] = a[i, j];
}
}
for (int i = i1 + 1; i < rows; i++)
{
for (int j = 0; j < j1; j++)
{
na[i - 1, j] = a[i, j];
}
for (int j = j1 + 1; j < rows; j++)
{
na[i - 1, j - 1] = a[i, j];
}
}
return(na);
}
