Csharp 分子 MC 模拟不平衡

假设一个polymer 链中有N个单体.我想用bead-spring模型来模拟它的运动.然而，没有应用周期性边界条件.因为，点的生成是这样的，它们永远不会越过边界.

所以，我写了下面的程序.

• Polymer chain simulation with Monte Carlo method

我用了100万步.能量并不像预期的那样波动.走了几千步后，曲线就完全变平了.

X轴为步数.Y轴是总能量.

有人能判断一下源代码，告诉我应该修改什么吗？

注:我特别关注计算polymer 总能量的函数.

算法可能不正确.

    public double GetTotalPotential()
    {
        double totalBeadPotential = 0.0;
        double totalSpringPotential = 0.0;

        // calculate total bead-energy
        for (int i = 0; i < beadsList.Count; i++)
        {
            Bead item_i = beadsList[i];
            Bead item_i_plus_1 = null;

            try
            {
                item_i_plus_1 = beadsList[i + 1];

                if (i != beadsList.Count - 1)
                {
                    // calculate total spring energy.
                    totalSpringPotential += item_i.GetHarmonicPotential(item_i_plus_1);
                }
            }
            catch { }

            for (int j = 0; j < beadsList.Count; j++)
            {
                if (i != j)
                {
                    Bead item_j = beadsList[j];
                    totalBeadPotential += item_i.GetPairPotential(item_j);
                    //Console.Write(totalBeadPotential + "\n");
                    //Thread.Sleep(100);
                }
            }
        }

        return totalBeadPotential + totalSpringPotential;
    }