function A = qrGivens(A)
[m,n]=size(A);

for j=1:n
  for i=j+1:m 
    tmp = sinPhi(A(j,j),A(i,j)); 
    A([j,i],j:end) = [sqrt(1-tmp^2),-tmp;tmp,sqrt(1-tmp^2)]* A([j,i],j:end);
    A(i,j) = tmp;
  end 
end
