public /**/ double quality()
{
return(SpecializedOps_ZDRM.qualityTriangular(LU));
}
/**
* a specialized version of solve that avoid additional checks that are not needed.
*/
public void _solveVectorInternal(double[] vv)
{
// Solve L*Y = B
solveL(vv);
// Solve U*X = Y;
TriangularSolver_ZDRM.solveU(dataLU, vv, n);
}
override public /**/ double quality()
{
return(SpecializedOps_ZDRM.qualityTriangular(R));
}
/**
* Solves for X using the QR decomposition.
*
* @param B A matrix that is n by m. Not modified.
* @param X An n by m matrix where the solution is written to. Modified.
*/
override public void solve(ZMatrixRMaj B, ZMatrixRMaj X)
{
UtilEjml.checkReshapeSolve(numRows, numCols, B, X);
int BnumCols = B.numCols;
// solve each column one by one
for (int colB = 0; colB < BnumCols; colB++)
{
// make a copy of this column in the vector
for (int i = 0; i < numRows; i++)
{
int indexB = (i * BnumCols + colB) * 2;
a.data[i * 2] = B.data[indexB];
a.data[i * 2 + 1] = B.data[indexB + 1];
}
// Solve Qa=b
// a = Q'b
// a = Q_{n-1}...Q_2*Q_1*b
//
// Q_n*b = (I-gamma*u*u^T)*b = b - u*(gamma*U^T*b)
for (int n = 0; n < numCols; n++)
{
double[] u = QR[n];
double realVV = u[n * 2];
double imagVV = u[n * 2 + 1];
u[n * 2] = 1;
u[n * 2 + 1] = 0;
QrHelperFunctions_ZDRM.rank1UpdateMultR(a, u, 0, gammas[n], 0, n, numRows, temp.data);
u[n * 2] = realVV;
u[n * 2 + 1] = imagVV;
}
// solve for Rx = b using the standard upper triangular solver
TriangularSolver_ZDRM.solveU(R.data, a.data, numCols);
// save the results
for (int i = 0; i < numCols; i++)
{
int indexB = (i * BnumCols + colB) * 2;
X.data[indexB] = a.data[i * 2];
X.data[indexB + 1] = a.data[i * 2 + 1];
}
}
}
