public override int GetHashCode()
        {
            var hashCode = -929212920;

            hashCode = hashCode * -1521134295 + EqualityComparer <double[, ]> .Default.GetHashCode(matrix);

            hashCode = hashCode * -1521134295 + A11.GetHashCode();
            hashCode = hashCode * -1521134295 + A12.GetHashCode();
            hashCode = hashCode * -1521134295 + A13.GetHashCode();
            hashCode = hashCode * -1521134295 + A21.GetHashCode();
            hashCode = hashCode * -1521134295 + A22.GetHashCode();
            hashCode = hashCode * -1521134295 + A23.GetHashCode();
            hashCode = hashCode * -1521134295 + A31.GetHashCode();
            hashCode = hashCode * -1521134295 + A32.GetHashCode();
            hashCode = hashCode * -1521134295 + A33.GetHashCode();
            return(hashCode);
        }