共价模型单种自旋的电子组态的索引方法

来源：互联网发布：周末网络国债理财机构编辑：程序博客网时间：2024/05/16 16:17

此方法来自武剑的论文，见 Jian Wu and Yuansheng Jiang, J. Comp. Chem. 2000, 21, 856.

此处的main函数只是用于测试算法是否正确，此算法最后会作为另一个程序的子函数。

/*  luozhen, 2015-05-20*///Available only for Sz = 0#include <iostream>#include <vector>#include <bitset>using namespace std;//define the total number of atomsconst int atoms = 6;//combinatorial number calculation//compiled to 64bit binary, the maxinum number under handle is C(32,16)int _combinatorial(int n, int k){if(k > n)return 0;if(k > n/2)k = n - k;if(k == 1) {return n;} else if(k == 0) {return 1;} else {return _combinatorial(n-1, k-1) + _combinatorial(n-1, k);}}//Applied to Alpha electronsint GetAlphaIndex(bitset<atoms> _wave){vector<int> alpha_site;alpha_site.push_back(0);for(int ix = 0; ix != atoms; ++ ix) {if(_wave[ix]) {alpha_site.push_back(ix+1);}}int index = 1;for(int i = 1; i != atoms/2+1; ++ i) {if(alpha_site[i] - alpha_site[i-1] > 1) {for(int j = 1; j != alpha_site[i] - alpha_site[i-1]; ++ j) {index += _combinatorial(atoms - alpha_site[i-1] -j, atoms/2 - i);}}}return index;}//to check whether the code is rightint main(){bitset<atoms> iwave;iwave.reset();int site1, site2, site3;cout<<"Enter site1, site2 and site3 (1 <= site_i <= "<<atoms<<"):"<<endl;cin>>site1>>site2>>site3;iwave.set(site1-1);iwave.set(site2-1);iwave.set(site3-1);int temp = GetAlphaIndex(iwave);cout<<"config: "<<site1<<site2<<site3<<"\tbitset: "<<iwave<<"\tindex: "<<GetAlphaIndex(iwave)<<endl;return 0;}

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