/*!
Applies the inverse.
*/
void apply_Inverse(MatrixXcd& matrix, int mStart) {
int n = matrix.cols();
int start = nStart-mStart;
if (isLeaf == true) {
matrix.block(start, 0, nSize, n) = Kinverse.solve(matrix.block(start, 0, nSize, n));
}
else if (isLeaf == false) {
// Computes temp = Vinverse*matrix
MatrixXcd temp(nRank[0]+nRank[1], n);
temp.block(0, 0, nRank[0] , n) = Vinverse[1]*matrix.block(start+child[0]->nSize, 0 , child[1]->nSize, n);
temp.block(nRank[0], 0, nRank[1] , n) = Vinverse[0]*matrix.block(start, 0 , child[0]->nSize, n);
// Computes tempSolve = Kinverse\temp
MatrixXcd tempSolve = Kinverse.solve(temp);
// Computes matrix = matrix-Uinverse*tempSolve
matrix.block(start, 0, child[0]->nSize, n) = matrix.block(start, 0, child[0]->nSize, n) - Uinverse[0]*tempSolve.block(0, 0, nRank[0], n);
matrix.block(start + child[0]->nSize, 0, child[1]->nSize, n) = matrix.block(start + child[0]->nSize, 0, child[1]->nSize, n) - Uinverse[1]*tempSolve.block(nRank[0], 0, nRank[1], n);
}
};
void compute_K() {
if (isLeaf == false) {
int m0 = V[0].rows();
int m1 = V[1].rows();
K = MatrixXcd::Identity(m0+m1, m0+m1);
K.block(0, m1, m1, m0) = Vinverse[1]*Uinverse[1];
K.block(m1, 0, m0, m1) = Vinverse[0]*Uinverse[0];
}
};
/*!
Matrix matrix product.
*/
void matrix_Matrix_Product(MatrixXcd& x, MatrixXcd& b) {
int n = x.cols();
if (isLeaf == true) {
b.block(nStart, 0, nSize, n) = b.block(nStart, 0, nSize, n) + K*x.block(nStart, 0, nSize, n);
}
else if (isLeaf == false) {
int n0 = child[0]->nStart;
int n1 = child[1]->nStart;
int m0 = child[0]->nSize;
int m1 = child[1]->nSize;
b.block(n0, 0, m0, n) = b.block(n0, 0, m0, n) + U[0]*(V[1]*x.block(n1, 0, m1, n));
b.block(n1, 0, m1, n) = b.block(n1, 0, m1, n) + U[1]*(V[0]*x.block(n0, 0, m0, n));
}
};
