enum Seaweed { Dry, Dryish, Damp, Soggy }; // 观察状态（海藻湿度）
//static void Main(string[] args)
//{
// 测试前向<a href="http://lib.csdn.net/base/datastructure" class='replace_word' title="算法与数据结构知识库" target='_blank' style='color:#df3434; font-weight:bold;'>算法</a>和后向算法
//CheckForwardAndBackward();
//Console.WriteLine();
//// 测试维特比算法
//CheckViterbi();
//Console.WriteLine();
//// 测试HMM学习算法
//CheckBaumWelch();
//}
// 测试前向算法和后向算法
public static string CheckForwardAndBackward()
{
// 状态转移矩阵
Double[,] A =
{
{ 0.500, 0.375, 0.125 },
{ 0.250, 0.125, 0.625 },
{ 0.250, 0.375, 0.375 }
};
// 混淆矩阵
Double[,] B =
{
{ 0.60, 0.20, 0.15, 0.05 },
{ 0.25, 0.25, 0.25, 0.25 },
{ 0.05, 0.10, 0.35, 0.50 }
};
// 初始概率向量
Double[] PI = { 0.63, 0.17, 0.20 };
// 观察序列
Int32[] OB = { (Int32)Seaweed.Dry, (Int32)Seaweed.Damp, (Int32)Seaweed.Soggy };
// 初始化HMM模型
HMM hmm = new HMM(A.GetLength(0), B.GetLength(1));
hmm.A = A;
hmm.B = B;
hmm.PI = PI;
// 观察序列的概率
//Console.WriteLine("------------前向算法：双精度运算-----------------");
Double ProbabilityFor = hmm.Forward(OB);
//Console.WriteLine("Probability =" + Probability.ToString("0.###E+0"));
//Console.WriteLine();
// 观察序列的概率
//Console.WriteLine("------------后向算法：双精度运算-----------------");
Double ProbabilityBack = hmm.Backward(OB);
//Console.WriteLine("Probability =" + Probability.ToString("0.###E+0"));
return(ProbabilityFor.ToString("0.###E+0") + "|" + ProbabilityBack.ToString("0.###E+0"));
}