AStridedMatrix u_sub = U.subMatrix(w, width-w, 0, 1);
// SimpleMatrix A_sub = A.extractMatrix(w,width,w,width);
AStridedMatrix A_sub = A.subMatrix(w,width-w,w,width-w);
// SimpleMatrix expected = I.minus(u_sub.mult(u_sub.transpose()).scale(gamma)).mult(A_sub);
Matrix temp1 = Multiplications.multiply(u_sub, u_sub.getTranspose());
temp1.scale(gamma);
I.sub(temp1);
Matrix expected = Multiplications.multiply(I, A_sub);
qr.updateA(w,U.asDoubleArray(),gamma,tau);