郁闷之春的专栏

原理请参见鄙人前面的一篇文章

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace Viterbi{class Program{const int m = 2; //隐含状态数const int n = 3; //观察状态数static int[] sArray = new int[n]; //隐含状态序列static int[] oArray = { 0, 1, 2 }; //可观察状态序列static double[] iArray = { 0.6, 0.4 };//初始概率矩阵static double[,] aArray = { { 0.7, 0.3 }, { 0.4, 0.6 } };//转移概率矩阵static double[,] bArray = { { 0.5, 0.4, 0.1 }, { 0.1, 0.3, 0.6 } };//发射概率矩阵static double[,] resultArray = new double[n, m];//保存结果static void Main(string[] args){Viterbi(sArray, oArray, iArray, aArray, bArray);foreach (int i in sArray){Console.Write(i);}Console.ReadKey();}static void Viterbi(int[] s, int[] o, double[] i, double[,] a, double[,] b){for (int j = 0; j < m; j++){resultArray[0, j] = iArray[j] * bArray[j, oArray[0]];}for (int j = 1; j < n; j++){for (int p = 0; p < m; p++){for (int k = 0; k < m; k++){double tmp = resultArray[j – 1, p] * aArray[p, k] * bArray[k, oArray[j]];if (tmp > resultArray[j, k])resultArray[j, k] = tmp;}}}for (int j = 0; j < n; j++){double tmp = resultArray[j, 0];sArray[j] = 0;for (int p = 0; p < m; p++){if (resultArray[j, p] > tmp)sArray[j] = p;}}}}}运行结果如下：

输入可观察状态序列：012

隐含状态序列：001

，力微休负重，言轻莫劝人。