/**
* <p>
* Creates a reflector from the provided vector and gamma.<br>
* <br>
* Q = I - γ u u<sup>H</sup><br>
* </p>
*
* @param u A vector. Not modified.
* @param gamma To produce a reflector gamma needs to be equal to 2/||u||.
* @return An orthogonal reflector.
*/
public static ZMatrixRMaj createReflector(ZMatrixRMaj u, double gamma)
{
if (!MatrixFeatures_ZDRM.isVector(u))
{
throw new ArgumentException("u must be a vector");
}
ZMatrixRMaj Q = CommonOps_ZDRM.identity(u.NumElements);
CommonOps_ZDRM.multAddTransB(-gamma, 0, u, u, Q);
return(Q);
}
/**
* <p>
* Creates a reflector from the provided vector.<br>
* <br>
* Q = I - γ u u<sup>T</sup><br>
* γ = 2/||u||<sup>2</sup>
* </p>
*
* @param u A vector. Not modified.
* @return An orthogonal reflector.
*/
public static ZMatrixRMaj createReflector(ZMatrixRMaj u)
{
if (!MatrixFeatures_ZDRM.isVector(u))
{
throw new ArgumentException("u must be a vector");
}
double norm = NormOps_ZDRM.normF(u);
double gamma = -2.0 / (norm * norm);
ZMatrixRMaj Q = CommonOps_ZDRM.identity(u.NumElements);
CommonOps_ZDRM.multAddTransB(gamma, 0, u, u, Q);
return(Q);
}
public static ZMatrixRMaj checkIdentity(ZMatrixRMaj A, int numRows, int numCols)
{
if (A == null)
{
return(CommonOps_ZDRM.identity(numRows, numCols));
}
else if (numRows != A.numRows || numCols != A.numCols)
{
throw new ArgumentException("Input is not " + numRows + " x " + numCols + " matrix");
}
else
{
CommonOps_ZDRM.setIdentity(A);
}
return(A);
}