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| // TrainXor_RandomSearch.cpp
// UMUTech @ 2018-07-05 23:45:52
// Be aware that I'm only a novice to ANN. My apologies for any wrong info.
//
#include <algorithm>
#include <iostream>
#include <random>
std::default_random_engine random_engine;
void RandomizeW(double* w, size_t size) {
std::uniform_real_distribution<double> r(0, 1);
for (size_t i = 0; i < size; ++i) {
w[i] = r(random_engine);
}
}
void PrintW(double* w, size_t size) {
for (size_t i = 0; i < size; ++i) {
std::cout << i << "\t" << w[i] << "\n";
}
}
double ActivationFunction(double x) {
// ReLU
return std::max(0.0, x);
}
double AnnRun(const double x[2], double* w) {
// bias 乘了 -1，让结果更好地收敛到 [0, 1]
double f = ActivationFunction(x[0] * w[0] + x[1] * w[1] - w[2]);
double g = ActivationFunction(x[0] * w[3] + x[1] * w[4] - w[5]);
return ActivationFunction(f * w[6] + g * w[7] - w[8]);
}
int main() {
const double input[4][2] = {{0, 0}, {0, 1}, {1, 0}, {1, 1}};
const double expect_output[4] = {0, 1, 1, 0};
double last_error = 1000;
double w[3 * 3];
double w_copy[3 * 3];
std::random_device rd;
random_engine.seed(rd());
int train_count = 0;
for (; last_error > 0.01; ++train_count) {
if (train_count % 10000 == 0) {
std::cout << "Randomize\n";
RandomizeW(w, _countof(w));
}
memcpy(w_copy, w, sizeof(w));
// 随机改变 w
std::uniform_real_distribution<double> r(-0.5, 0.5);
for (int i = 0; i < 3 * 3; ++i) {
w[i] += r(random_engine);
}
double error = pow(AnnRun(input[0], w) - expect_output[0], 2.0);
error += pow(AnnRun(input[1], w) - expect_output[1], 2.0);
error += pow(AnnRun(input[2], w) - expect_output[2], 2.0);
error += pow(AnnRun(input[3], w) - expect_output[3], 2.0);
if (error < last_error) {
// 错误率更小，保存
last_error = error;
} else {
// 恢复 w
memcpy(w, w_copy, sizeof(w));
}
}
printf("Finished in %d loops.\n", train_count);
PrintW(w, _countof(w));
/* Run the network and see what it predicts. */
printf("Output for [%1.f, %1.f] is %1.f.\n", input[0][0], input[0][1],
AnnRun(input[0], w));
printf("Output for [%1.f, %1.f] is %1.f.\n", input[1][0], input[1][1],
AnnRun(input[1], w));
printf("Output for [%1.f, %1.f] is %1.f.\n", input[2][0], input[2][1],
AnnRun(input[2], w));
printf("Output for [%1.f, %1.f] is %1.f.\n", input[3][0], input[3][1],
AnnRun(input[3], w));
return 0;
}
|
