function?xest?=?pocs（Phi?l1val?y?niter）
%?Syntax?:
%??xest?=?cspocs_l1（Phi?aPhi?l1val?y?niter）
%
%?Description?:?Testing?Candes?and?Romberg?POCS?（alternate?Projection?Onto
%?Convex?Sets）?for?CS?recovery?aka?recovering?of?x?from?y?=?Phi*x?when
%?size（Phi1）?%?
%?In?:
%?*?Phi?aPhi?:?Measurement?matrix?and?its?reconstruction
%?*?l1val?:?the?l1?norm?of?the?intial?signal?x?i.e.?norm（x1）
%?*?niter?:?maximun?number?of?alternate?projections.
%
%?Out?:
%?*?xest?:?the?recovered?（or?estimated）?signal?x
%
%?Author?of?this?mfile?:?L.?Jacques?LTS2/EPFL?2008.
%????
%?Reference?:?
%????Algo?described?in?“Practical?Signal?Recovery?from?Random?Projections“
%????Emmanuel?Cand鑣?and?Justin?Romberg
%?Example?:
%?>>?N=128;?K=20;
%?>>?x=[rand（1K）?zeros（1N-K）]‘;?x