Inputs: CS matrix D, measurement , upward extending coefficient l, weighting value c, and  iterative number K, wavelet transform level J, =  Outputs: approximated signal  Initialize: = , = , k = 0, = {1,2,…, (= N/2^{J})}   While halting criterion false do  (1) k = k +1  (2)  (3)  (4) construct upsidedown tree  (i) =  (5)  (6)  (7)  end while   return 
