神经网络C语言实现

#i n c l u d e"" #include <>

const double e = ;

//设置一个神经网络

//有一个隐藏层（含有两个节点）

//输出层有一个节点

//输入数据是二维（两个节点）

//一个样本数据为：x = , 标签为

//初始权值输入节点1到隐藏层：，

//输入节点2到隐藏层：,

//隐藏层到输出层初始权值为：,

//学习速率为1

double changeWeightFromHiddenToOutput(double cost,double output,double hiddenLayerCode)

{

double result=0;

result = cost*output*(1-output)*hiddenLayerCode;

return result;

}

double changeWeightFromInputToHidden(double cost,double output,double weightOfHiddenCodeToOutput,double weightOfHiddenCode,double inputNum)

double result=0;

result = cost*output*(1-output)*weightOfHiddenCodeToOutput*weightOfHiddenC ode*(1-weightOfHiddenCode)*inputNum;

return result;

}

double sigmoidFunction(double x)

{

double result=0;

result = 1/(1+pow(e,-x));

return result;

}

double costFunction(double originalSignal,double outputOfOurCalculation)

{

//此处采取的损失函数是最小二乘法

double cost=0;

cost = (1/*(originalSignal-outputOfOurCalculation)*(originalSignal-outpu tOfOurCalculation);

return cost;

double upDateWeightFunction(double originalValue,double gradient) {

double updatedWeight=originalValue;

updatedWeight = updatedWeight - fabs(gradient);

return updatedWeight;

}

int main(void)

{

double weightFromInputToHidden[][2]={,,,};

double weightFromHiddenToOutput[]={,};

double firstHiddenCode,secondHiddenCode,outputCode;

double inputValue[] ={,};

double originalSignal = ;

double cost=0;

double weightChangeNum=0;

double addWeightSum = 0;

firstHiddenCode = 0;

secondHiddenCode = 0;

outputCode = 0;

//前向传播

addWeightSum = weightFromInputToHidden[0][0]*inputValue[0] +

weightFromInputToHidden[1][0]*inputValue[1];

firstHiddenCode = sigmoidFunction(addWeightSum);

addWeightSum = weightFromInputToHidden[0][1]*inputValue[0] + weightFromInputToHidden[1][1]*inputValue[1];

secondHiddenCode = sigmoidFunction(addWeightSum);

addWeightSum = weightFromHiddenToOutput[0]*firstHiddenCode + weightFromHiddenToOutput[1]*secondHiddenCode;

outputCode = sigmoidFunction(addWeightSum);

//计算误差

cost = costFunction(originalSignal,outputCode);

printf("\n\n(0)firNode:[%f] secNode:[%f] outNode:[%f] cost:%f",firstHiddenCode,secondHiddenCode,outputCode,cost);

printf("\n\n\t\t输入到隐藏层的权值:\t\t");

for(int i=0;i<2;i++)

{

printf("\n\t\t");

for(int j=0;j<2;j++)

printf(" %lf ",weightFromInputToHidden[i][j]);

}

printf("\n\n\t\t隐藏层到输出的权值:\n\t\t");

for(i=0;i<2;i++)

{