c ++-default_random_engine始终创建相同系列的数字

本文介绍了c ++-default_random_engine始终创建相同系列的数字的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在使用神经网络，所以我想随机创建权重.因此，如果我创建30个神经网络，那么每个神经网络最终都具有相同的权重(假定是随机的)，因此当我给它们提供相同的输入时，输出应该是相同的，否则就不会输出.有帮助吗?

I am working with neural networks, and I want to create the weights randomly. SO if I create 30 Neural networks every single one of them ends up having the same weights(supposed to be random) so when i give them all the same input the output is the same, when it shouldn't. Any help?

这是主要功能

int main(){
std::vector<Improved_NN> v;
std::random_device rd;
std::default_random_engine generator(rd());
std::uniform_real_distribution<double> distribution(-1.0,1.0);
for(int i = 0; i < 30; i++)
{
    Improved_NN temp;
    temp.initialize_weights(generator, distribution);
    v.push_back(temp);
}

Board temp;

for(int i = 0; i < 30; i++)
{
    std::cout <<"\n" << v[i].executeFromExternal(temp);
}

而initialize_weights在这里:

And the initialize_weights is here:

 void Improved_NN::initialize_weights(std::default_random_engine gen,std::uniform_real_distribution<double> dist){
int k,v = 0;
for(k = 0;k<NUM_HIDDEN_1;k++){
    for(v = 0 ; v < NUM_INPUTS; v++){
        mlp_t.w_h1_i[k][v]=dist(gen);
        //std::cout<<mlp_t.w_h1_i[k][v]<<std::endl;
    }
}
for(k = 0;k<NUM_HIDDEN_2;k++){
    for(v = 0 ; v < NUM_HIDDEN_1; v++){
        mlp_t.w_h2_h1[k][v]=dist(gen);
        //std::cout<<mlp_t.w_h2_h1[k][v]<<std::endl;
    }
}
for(k = 0;k<NUM_HIDDEN_3;k++){
    for(v = 0 ; v < NUM_HIDDEN_2; v++){
        mlp_t.w_h3_h2[k][v]=dist(gen);
        //std::cout<<mlp_t.w_h3_h2[k][v]<<std::endl;
    }
}
    for (int a = 0 ; a < NUM_HIDDEN_3;a++){
        mlp_t.w_o_h[0][a] = dist(gen);
        //std::cout<<mlp_t.w_o_h[0][a]<<std::endl;
    }
}

这是我每次执行时得到的输出.

This is the output i get every time i execute.

0.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.5214580.521458

非常感谢您.

推荐答案

好了，就像普通的rand()一样，您需要为生成器提供初始种子，该种子必须具有不同的值，以便生成器生成不同的序列:

Well, as with plain old rand() you need to provide initial seed for the generator which needs to be different value in order for generator to generate different sequence:

    std::random_device rd;
    std::default_random_engine generator(rd());

此外，正如user3018144所指出的，请使用单个生成器，而不要使用30个不同的生成器:

Also, as user3018144 pointed out, use single generator, instead of 30 different:

int main(){
    std::vector<Improved_NN> v;
    std::random_device rd;
    std::default_random_engine generator(rd());
    std::uniform_real_distribution<double> distribution(-1.0,1.0);

    for(int i = 0; i < 30; i++)
    {
        Improved_NN temp;

        /*Problem is here*/
        temp.initialize_weights(generator, distribution);
        v.push_back(temp);
    }

    Board temp;

    for(int i = 0; i < 30; i++)
    {
        std::cout <<"\n" << v[i].executeFromExternal(temp);
    }


//for the number of generations, do this....
}

另外，就在这里:

 void Improved_NN::initialize_weights(std::default_random_engine gen,std::uniform_real_distribution<double> dist){

您正在按值传递生成器，这将创建现有生成器的副本.而是通过引用传递:

you're passing the generators by value, which will create a copy of the existing generator. Pass by reference instead:

 void Improved_NN::initialize_weights(std::default_random_engine& gen, std::uniform_real_distribution<double>& dist){

这篇关于c ++-default_random_engine始终创建相同系列的数字的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！