Constrained non-Markovian Monte Carlo modelling of the evolution   equation in QCD
  A new class of the constrained Monte Carlo (CMC) algorithms for the QCD evolution equation was recently discovered. The constraint is imposed on the type and the total longitudinal energy of the parton exiting QCD evolution and entering a hard process. The efficiency of the new CMCs is found to be reasonable. 
S. Jadach and M. Skrzypek