#include <math.h>
#include <stdio.h>
#include <string>
#include <vector>
#include "mnist_common.h"
using std::vector;
float accuracy(
const array &predicted,
const array &target) {
array val, plabels, tlabels;
max(val, tlabels, target, 1);
max(val, plabels, predicted, 1);
return 100 * count<float>(plabels == tlabels) / tlabels.
elements();
}
array deriv(
const array &out) {
return out * (1 - out); }
double error(
const array &out,
const array &pred) {
array dif = (out - pred);
return sqrt((
double)(sum<float>(dif * dif)));
}
}
class rbm {
private:
public:
rbm(int v_size, int h_size)
: weights(
randu(h_size, v_size) / 100.f)
}
void train(
const array &in,
double lr,
int num_epochs,
int batch_size,
bool verbose) {
const int num_samples = in.
dims(0);
const int num_batches = num_samples / batch_size;
for (int i = 0; i < num_epochs; i++) {
double err = 0;
for (int j = 0; j < num_batches - 1; j++) {
int st = j * batch_size;
int en =
std::min(num_samples - 1, st + batch_size - 1);
int num = en - st + 1;
array h_pos = sigmoid_binary(
tile(h_bias, num) +
sigmoid_binary(
tile(v_bias, num) +
matmul(h_pos, weights));
array h_neg = sigmoid_binary(
tile(h_bias, num) +
array delta_w = lr * (c_pos - c_neg) / num;
array delta_vb = lr *
sum(v_pos - v_neg) / num;
array delta_hb = lr *
sum(h_pos - h_neg) / num;
weights += delta_w;
v_bias += delta_vb;
h_bias += delta_hb;
if (verbose) { err += error(v_pos, v_neg); }
}
if (verbose) {
printf("Epoch %d: Reconstruction error: %0.4f\n", i + 1,
err / num_batches);
}
}
}
}
};
class dbn {
private:
const int in_size;
const int out_size;
const int num_hidden;
const int num_total;
std::vector<array> weights;
std::vector<int> hidden;
}
vector<array> forward_propagate(
const array &input) {
vector<array> signal(num_total);
signal[0] = input;
for (int i = 0; i < num_total - 1; i++) {
array in = add_bias(signal[i]);
}
return signal;
}
void back_propagate(
const vector<array> signal,
const array &target,
const double &alpha) {
array out = signal[num_total - 1];
array err = (out - target);
for (int i = num_total - 2; i >= 0; i--) {
array in = add_bias(signal[i]);
array delta = (deriv(out) * err).T();
out = signal[i];
}
}
public:
dbn(const int in_sz, const int out_sz, const std::vector<int> hidden_layers)
: in_size(in_sz)
, out_size(out_sz)
, num_hidden(hidden_layers.size())
, num_total(hidden_layers.size() + 2)
, weights(hidden_layers.size() + 1)
, hidden(hidden_layers) {}
void train(
const array &input,
const array &target,
double lr_rbm = 1.0,
double lr_nn = 1.0, const int epochs_rbm = 15,
const int epochs_nn = 300, const int batch_size = 100,
double maxerr = 1.0, bool verbose = false) {
for (int i = 0; i < num_hidden; i++) {
if (verbose) { printf("Training Hidden Layer %d\n", i); }
int visible = (i == 0) ? in_size : hidden[i - 1];
rbm r(visible, hidden[i]);
r.train(X, lr_rbm, epochs_rbm, batch_size, verbose);
X = r.prop_up(X);
weights[i] = r.get_weights();
if (verbose) { printf("\n"); }
}
weights[num_hidden] =
0.05 *
randu(hidden[num_hidden - 1] + 1, out_size) - 0.0025;
const int num_samples = input.
dims(0);
const int num_batches = num_samples / batch_size;
for (int i = 0; i < epochs_nn; i++) {
for (int j = 0; j < num_batches; j++) {
int st = j * batch_size;
int en =
std::min(num_samples - 1, st + batch_size - 1);
vector<array> signals = forward_propagate(x);
array out = signals[num_total - 1];
back_propagate(signals, y, lr_nn);
}
int st = (num_batches - 1) * batch_size;
int en = num_samples - 1;
double err = error(out, target(
seq(st, en),
span));
if (err < maxerr) {
printf("Converged on Epoch: %4d\n", i + 1);
return;
}
if (verbose) {
if ((i + 1) % 10 == 0)
printf("Epoch: %4d, Error: %0.4f\n", i + 1, err);
}
}
}
vector<array> signal = forward_propagate(input);
array out = signal[num_total - 1];
return out;
}
};
int dbn_demo(bool console, int perc) {
printf("** ArrayFire DBN Demo **\n\n");
array train_images, test_images;
array train_target, test_target;
int num_classes, num_train, num_test;
float frac = (float)(perc) / 100.0;
setup_mnist<true>(&num_classes, &num_train, &num_test, train_images,
test_images, train_target, test_target, frac);
int feature_size = train_images.
elements() / num_train;
array train_feats =
moddims(train_images, feature_size, num_train).
T();
array test_feats =
moddims(test_images, feature_size, num_test).
T();
train_target = train_target.
T();
test_target = test_target.
T();
vector<int> layers;
layers.push_back(100);
layers.push_back(50);
dbn network(train_feats.
dims(1), num_classes, layers);
network.train(train_feats, train_target,
0.2,
4.0,
15,
250,
100,
0.5,
true);
array train_output = network.predict(train_feats);
array test_output = network.predict(test_feats);
for (int i = 0; i < 100; i++) { network.predict(test_feats); }
printf("\nTraining set:\n");
printf("Accuracy on training data: %2.2f\n",
accuracy(train_output, train_target));
printf("\nTest set:\n");
printf("Accuracy on testing data: %2.2f\n",
accuracy(test_output, test_target));
printf("\nTraining time: %4.4lf s\n", train_time);
printf("Prediction time: %4.4lf s\n\n", test_time);
if (!console) {
test_output = test_output.
T();
display_results<true>(test_images, test_output, test_target.
T(), 20);
}
return 0;
}
int main(int argc, char **argv) {
int device = argc > 1 ? atoi(argv[1]) : 0;
bool console = argc > 2 ? argv[2][0] == '-' : false;
int perc = argc > 3 ? atoi(argv[3]) : 60;
try {
return dbn_demo(console, perc);
return 0;
}