C语言求信息熵,条件熵,联合熵

1、# iiiclude<stdio.h># iiiclude<math.h>define u 20mt ij 卫,m;float H_X.H_YH_XYH_Xp Yfypxu u.Pxu.H_YpX.Pyu ,Pxpyu u.Pxyu u;/*H_X=H(X)平均自信息；H_XY=H(XY)联合矯;H_XpY=H(X|Y)、H_YpX=H(Y|X)条件爛；Pypxij=P(yj|xi)条件概率;Pxi=P(xi)发 xi的概率;H_XpY=H(Y/X)条件爛;Pv|j=P(yU)收到 yj的概率；?xpyij=P(xi/yj)条件概率;Pxyij=P(xiyj)联合概率*

2、/*定义以2为底的对数函数*/float log2(float x)float z;z=(float)(log(x)/log(2);return z;/*求信源爛)函数*/float entropy(float *xjnt n)float z=0;fbr(i=i;i<=n;i-H-)z+=(*(x+i)*log2(l/(*(x+i);return z;/*求联合嫡的函数*/float joint_entropy(float (*p)u) float z=0;for(j=l；j<=nij+)z+=*(pi+j)*log2(l/(*(pi+j); return z; main()flo

3、at s=0;prmtf(niiplease in put the dimension ofX and 'Y'n”)；scanf(M%d&m);prmtf(niiThe dunension of X is n=%d'nThe dimension of Y is m=%d nPlease mput the condition probability:P(yj/xi),H4i,m);prmtf(n(after you input one number please click the rentei,)iiH)；产条件概率P(yj/xi)赋值引fdr(i=l;i<

4、;=n;i+)for(j=lJ<=m；j+)pnntf(” P(y%d/x%d)=“,j,i);scanff% 玖&Pypxij);prmtf(nplease mput P(xi):(after you mput one number please click the ,enter,)nH);foi(i=l;i<=n;i+)printf(nP(x%d )=,i);scanf(H%f&Pxi);/*判断输入X的概率是否正确，不正确则退出程序*/fbr(i=l;i<=n;i+)if(Pxi<O)|(Pxi>l)piiiitf(nPlease input

5、 light value of piobabilityiiH);goto End_exe;s+=Pxi;if(s-l)*(s-l)>O.OOl)printfTlease mput the right value of probabilitynH);goto End_exe;fdr(i=l;i<=n;i+)s=0;for(j=l;j<=mJ-H-)s+=Pypxij;if(s-l)*(s-l)>0.001)printf(HPlease mput the right value of probabilitynH);goto End_exe;严计算 Pyj=P(yj)收到 y

6、j的概率;Pxpyij=P(xi/yj)条件概率;Pxyi=P(xiy|j)联合 概率*7fbr(i=l;i<=n;i+)for(j=lj<=mj-H-)Pxyi|j=Pypxi|j*Pxi;pimtf("Px%dy%d=%fn',ij,Pxyij);for(j=l;j<=mj+)s=0;fbr(i=l;i<=n;i-H-)s+=Pxyi|j；Pyj=s；pi-mtf("P(y%d)=%fui"j,Py|j);fbi(i=l;i<=n;i+)for(j=lj<=mj+)Pxpyij=Pxyi|j/Pylj;piintf(

7、MP(x%d/y%d )=%fn,ij,Pxpyi j);严结束 计算Pyj=P(yj)收到yj的概率；Pxpyij=P(xi/yj)条件概率;Pxyfi j=P(xiyj)联合概率 */*输出信源爛H(X)*/H_X=entropy(Px.n);pnntf(HnThe entropy ofX :H(X)=%fiTH_X);H_Y=entropy(Py,m);pnntf(HnThe entropy ofY H(Y)=%fjT,H_Y);/*输出联合爛*/H_XY=j oint_entropy(Pxy); pnntf(HnThe joint entropy of X and Y iH(XY)=%fiT：H_XY);/*输