public Matrix Cofactor()
{
List <Vector> vectors = new List <Vector>();
for (int i = 0; i < ColumnLength; i++)
{
List <float> entries = new List <float>();
for (int j = 0; j < RowLength; j++)
{
Matrix cofactorMatrix = Copy();
cofactorMatrix.DeleteRowVector(i);
cofactorMatrix.DeleteColumnVector(j);
float cofactor = cofactorMatrix.Determinant();
cofactor *= ((-1) ^ (i + j));
entries.Add(cofactor);
}
vectors.Add(new Vector(entries));
}
return(new Matrix(vectors));
}
public float Determinant()
{
if (!IsSquare)
{
throw new ArithmeticException("Cannot compute the determinant of a non-square matrix");
}
if (RowLength == 2 && ColumnLength == 2)
{
//Det = ad - bc
return(this[0][0] * this[1][1] - this[0][1] * this[1][0]);
}
else
{
float det = 0;
for (int i = 0; i < RowLength; i++)
{
float scalar = this[0][i];
Matrix reducedMatrix = Copy();
reducedMatrix.DeleteRowVector(0);
reducedMatrix.DeleteColumnVector(i);
det += ((-1) ^ i) * scalar * reducedMatrix.Determinant();
}
return(det);
}
}
