在前面的高分子格子随机行走模型中，每个键的取向是完全是随机的，并且与前面相邻的键的取向是完全无关的。即高分子可以折回它已经占据的格点，这在物理上当然是不可能的。一个初步的补救方法是，不允许高分子往回折，即键矢量rn+1rn+1取向不可以是?rn?rn，只能随机从余下z?1z?1个取向中选一个取向。因此，在这个修正的模型中，rnrn已确定的情况下，rn+1rn+1平均值?rn+1?rn?rn+1?rn不是0，而是满足附件中的代码(In the preceding polymer lattice random walk model, the orientation of each bond is completely random and has nothing to do with the orientation of the adjacent key. That is, the polymer can return the lattice that it has occupied, which is of course not physically possible. A preliminary remedy is not allowed to fold back the bond vector of polymer, rn+1rn+1 orientation can not be - RN - RN, Z and 1z were only from the remaining 1 - orientation choose one orientation. Therefore, in this modified model, rnrn has been determined, the average value of rn+1rn+1 rn+1 RN rn+1 RN is not 0, but meet the annex to the code)