/**
* backward pass 2: update impression features (1) \hat{mu}' (mu_hat_prime_s) (2) \hat{V}'
* (v_hat_prime_s)
*/
public static void backward2(boolean update_grad) {
double c = (1 - lambda) * (1 - lambda) / (sigma * sigma);
for (int t1 = T - 1; t1 > t0; t1--) {
int t = t1 - t0;
// System.out.println("backward 2;\tt = " + t1);
if (t != T - 1 - t0) {
double[][] mu_prime_pre_t = mu_prime_s.get(t - 1); // \mu'^{t-1} [t-1]
double[][] mu_hat_prime_t = mu_hat_prime_s.get(t); // \hat{\mu}'^{t} [t-1]
double V_prime_pre_t = v_prime_s.get(t - 1); // V'^{t-1}
double V_hat_prime_t = v_hat_prime_s.get(t); // \hat{V}'{t}
/* calculate \hat{\mu}' at time t-1 */
double[][] mu_hat_prime_pre_t = new double[n][K];
double factor_1 = (sigma * sigma) / (V_prime_pre_t + sigma * sigma);
double factor_2 = (V_prime_pre_t) / (V_prime_pre_t + sigma * sigma);
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
mu_hat_prime_pre_t[i][k] =
factor_1 * mu_prime_pre_t[i][k] + factor_2 * mu_hat_prime_t[i][k];
}
/* calculate \hat{V}' at time t-1 */
double v_hat_prime_pre_t =
V_prime_pre_t + factor_2 * factor_2 * (V_hat_prime_t - V_prime_pre_t - sigma * sigma);
/* update \mu and V */
mu_hat_prime_s.set(t - 1, mu_hat_prime_pre_t);
v_hat_prime_s.set(t - 1, v_hat_prime_pre_t);
/* calculate and update grad_mu_hat_prime at time t-1 */
if (update_grad)
for (int s = 0; s < T - t0; s++) {
double[][] grad_mu_prime_pre_t_s = grad_mu_prime_s.get((t - 1) * (T - t0) + s);
double[][] grad_mu_hat_prime_t_s = grad_mu_hat_prime_s.get(t * (T - t0) + s);
double[][] grad_mu_hat_prime_pre_t_s = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
grad_mu_hat_prime_pre_t_s[i][k] =
factor_1 * grad_mu_prime_pre_t_s[i][k] + factor_2 * grad_mu_hat_prime_t_s[i][k];
}
grad_mu_hat_prime_s.set((t - 1) * (T - t0) + s, grad_mu_hat_prime_pre_t_s);
}
} else {
/*
* initial condition for backward pass:
* (1) \hat{\mu}'^{T} = \mu'^{T}
* (2) \hat{V}'^{T} = V'^{T}
* (3) \hat{grad_mu}'^{T/s} = grad_mu'^{T/s}, \forall s
*/
mu_hat_prime_s.set(t, mu_prime_s.get(t));
v_hat_prime_s.set(t, v_prime_s.get(t));
if (update_grad)
for (int s = 0; s < T - t0; s++) {
grad_mu_hat_prime_s.set(t * (T - t0) + s, grad_mu_prime_s.get(t * (T - t0) + s));
}
}
/* end for each t */
}
}
/*
* backward pass 1: update
* (1) \hat{mu} (mu_hat_s)
* (2) \hat{grad_mu} (grad_mu_hat_s)
* (3) \hat{V} (v_hat_s)
*/
public static void backward1(boolean update_grad) {
for (int t1 = T - 1; t1 > t0; t1--) {
int t = t1 - t0;
// System.out.println("backward 1;\tt = " + t1);
if (t != T - 1 - t0) {
double V_pre_t = v_s.get(t - 1); // V^{t-1}
double V_hat_t = v_hat_s.get(t); // \hat{V}^{t}
double[][] mu_pre_t = mu_s.get(t - 1); // \mu^{t-1}
double[][] mu_hat_t = mu_hat_s.get(t); // \hat{\mu}^{t} [t-1]
Matrix A_pre_t = new Matrix(AS.get(t - 1)); // A^{t-1}
Matrix hprime_pre_t = new Matrix(h_prime_s.get(t - 1)); // h'^{t-1}
Matrix ave_neighbors = A_pre_t.times(hprime_pre_t); // n * 1
/* calculate \hat{\mu} at time t-1 */
double factor_1 =
(1 - lambda) * V_pre_t / (sigma * sigma + (1 - lambda) * (1 - lambda) * V_pre_t);
double factor_2 = (sigma * sigma) / (sigma * sigma + (1 - lambda) * (1 - lambda) * V_pre_t);
double[][] mu_hat_pre_t = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
mu_hat_pre_t[i][k] =
factor_1 * (mu_hat_t[i][k] - lambda * ave_neighbors.get(i, k))
+ factor_2 * mu_pre_t[i][k];
}
/* calculate \hat{V} at time t-1 */
double V_hat_pre_t =
V_pre_t
+ factor_1
* factor_1
* (V_hat_t - (1 - lambda) * (1 - lambda) * V_pre_t - (sigma * sigma));
/* update \mu and V */
mu_hat_s.set(t - 1, mu_hat_pre_t);
v_hat_s.set(t - 1, V_hat_pre_t);
/* calculate and update grad_mu_hat at time t-1 */
if (update_grad)
for (int s = 0; s < T - t0; s++) {
double[][] grad_hat_t_s = grad_mu_hat_s.get(t * (T - t0) + s);
double[][] grad_pre_t_s = grad_mu_s.get((t - 1) * (T - t0) + s);
double[][] grad_hat_pre_t_s = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
grad_hat_pre_t_s[i][k] =
factor_1 * grad_hat_t_s[i][k] + factor_2 * grad_pre_t_s[i][k];
}
grad_mu_hat_s.set((t - 1) * (T - t0) + s, grad_hat_pre_t_s);
}
} else {
/*
* initial condition for backward pass:
* (1) \hat{mu}^{T} = mu^{T}
* (2) \hat{V}^{T} = V^{T}
* (3) \hat{grad_mu}^{T/s} = grad_mu^{T/s}, \forall s
*/
mu_hat_s.set(t, mu_s.get(t));
v_hat_s.set(t, v_s.get(t));
if (update_grad)
for (int s = 0; s < T - t0; s++) {
grad_mu_hat_s.set(t * (T - t0) + s, grad_mu_s.get(t * (T - t0) + s));
}
}
// Scanner sc = new Scanner(System.in);
// int gu; gu = sc.nextInt();
/* end for each t */
}
}
/** forward pass 2: update impression features (1) mu' (mu_prime_s) (2) variance V' (v_prime_s) */
public static void forward2(boolean update_grad) {
for (int t1 = t0; t1 < T; t1++) {
int t = t1 - t0;
// System.out.println("forward 2;\tt = " + t1);
if (t != 0) {
double delta_t_prime = delta_prime_s.get(t); // delta'_t
double[][] mu_prime_pre_t = mu_prime_s.get(t - 1); // mu'^{t-1} [t]
double[][] h_hat_prime_t = h_hat_prime_s.get(t); // \hat{h}'^{t} (n*1)
double V_prime_pre_t = v_prime_s.get(t - 1); // V'^{t-1} [t]
/* calculate \mu */
double[][] mu_prime_t = new double[n][K];
double factor_1 =
(delta_t_prime * delta_t_prime)
/ (delta_t_prime * delta_t_prime + sigma * sigma + V_prime_pre_t);
double factor_2 =
(sigma * sigma + V_prime_pre_t)
/ (delta_t_prime * delta_t_prime + sigma * sigma + V_prime_pre_t);
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
mu_prime_t[i][k] = factor_1 * mu_prime_pre_t[i][k] + factor_2 * h_hat_prime_t[i][k];
}
/* calculate V */
double v_prime_t = factor_2 * delta_t_prime * delta_t_prime;
/* update */
mu_prime_s.set(t, mu_prime_t);
v_prime_s.set(t, v_prime_t);
/* calculate and update grad_mu_prime */
if (update_grad)
for (int s = 0; s < T - t0; s++) {
double[][] grad_mu_prime_pre_t_s = grad_mu_prime_s.get((t - 1) * (T - t0) + s);
double[][] grad_mu_prime_t_s = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
grad_mu_prime_t_s[i][k] = factor_1 * grad_mu_prime_pre_t_s[i][k];
if (s == t) {
grad_mu_prime_t_s[i][k] += factor_2;
}
}
grad_mu_prime_s.set(t * (T - t0) + s, grad_mu_prime_t_s);
}
} else {
/* for \mu'_i: ignore the first term in the summation */
/* for V':
* option 1: use v_prime_init for all i
* option 2: ignore v_prime_{t-1}
*/
/*
double delta_t_prime = delta_prime_s.get(t); // delta'_t
double[][] h_hat_prime_t = h_prime_s.get(t); // \hat{h}'^{t} (n*1)
*/
/* calculate new round of parameters */
/*
double[] mu_prime_t = new double[n];
for (int i = 0; i < n; i++) {
double c = (sigma*sigma) / (sigma*sigma + delta_t_prime*delta_t_prime);
mu_prime_t[i] = c * h_hat_prime_t[i][0];
}
double v_prime_t = v_prime_init;
*/
/* update */
/*
mu_prime_s.set(t, mu_prime_t);
v_prime_s.set(t, v_prime_t);
*/
}
/* end for each t */
}
}
public static void test1(String seed) {
/* read, init data & parameters */
for (int t = t0; t < T; t++) {
// String fileDir = "../../data/graph/" + Integer.toString(t) + ".csv"; // original
// co-voting dataset
// String fileDir = "./data/" + Integer.toString(t) + ".csv"; // artificial toy dataset
String fileDir =
"../../data_sm/nips_17/out/"
+ seed
+ "/"
+ Integer.toString(t)
+ ".train.csv"; // nips dataset (smaller)
Map<Integer, Double> freq = FileParser.readCSVDict(fileDir);
double[][] G = new double[n][n];
double[][] A = new double[n][n];
double[][] mu = new double[n][K];
double[][] mu_hat = new double[n][K];
double[][] mu_prime = new double[n][K];
double[][] mu_hat_prime = new double[n][K];
double[][] h = new double[n][K];
double[][] h_hat = new double[n][K];
FileParser.readCSVGraph(fileDir, freq, G, A);
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
mu[i][k] = scale_0 * (rand.nextDouble() - 0.5);
mu_hat[i][k] = scale_0 * (rand.nextDouble() - 0.5);
mu_prime[i][k] = mu[i][k];
mu_hat_prime[i][k] = mu_hat[i][k];
h[i][k] = scale * (rand.nextDouble() - 0.5);
h_hat[i][k] = scale * (rand.nextDouble() - 0.5);
}
GS.add(G);
AS.add(A);
mu_s.add(mu);
mu_hat_s.add(mu_hat);
mu_prime_s.add(mu_prime);
mu_hat_prime_s.add(mu_hat_prime);
h_s.add(h);
h_prime_s.add(h);
h_hat_s.add(h_hat);
h_hat_prime_s.add(h);
/* for test */
delta_s.add(delta);
delta_prime_s.add(delta); // TODO previous: 0.1
v_s.add(0.1);
v_hat_s.add(0.1);
v_prime_s.add(0.1);
v_hat_prime_s.add(0.1);
System.out.println("done! t = " + t);
}
for (int t = t0; t < T; t++) {
for (int s = t0; s < T; s++) {
grad_mu_s.add(new double[n][K]);
grad_mu_hat_s.add(new double[n][K]);
grad_mu_prime_s.add(new double[n][K]);
grad_mu_hat_prime_s.add(new double[n][K]);
}
grad_h_hat_s.add(new double[n][K]);
grad_h_hat_prime_s.add(new double[n][K]);
}
/* end initialization */
/* outer for-loop */
double old_obj_1 = -1, old_obj_2 = -1;
for (int iter = 0; iter < MAX_ITER; iter++) {
// Scanner sc = new Scanner(System.in); int gu; gu = sc.nextInt();
System.out.println("====== iter = " + iter + " ======");
/** intrinsic feature * */
forward1(true, iter);
backward1(true);
compute_gradient1(iter);
double new_obj_1 = 0;
/* gradient descent: inner for-loop here */
int inner_iter_1 = 0;
while (inner_iter_1 < INNER_ITER) {
/* update variational parameters \hat{h} using gradient descent */
for (int t = 0; t < T - t0; t++) {
double[][] h_hat_t = h_hat_s.get(t);
double[][] grad_h_hat_t = grad_h_hat_s.get(t);
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
h_hat_t[i][k] += lr_1 * grad_h_hat_t[i][k];
}
h_hat_s.set(t, h_hat_t);
}
/* update \hat{\mu} and \hat{V}, since both are function of \hat{h} */
forward1(false, iter);
backward1(false);
double obj1 = compute_objective1();
if (inner_iter_1 % 10 == 0)
System.out.println("(1) iter = " + inner_iter_1 + ", obj 1 = " + obj1);
if (inner_iter_1 != 0 && obj1 < new_obj_1) {
lr_1 *= 0.8;
break;
}
new_obj_1 = obj1;
inner_iter_1 += 1;
}
if (inner_iter_1 == INNER_ITER) lr_1 *= 2;
/* sample */
for (int t = 0; t < T - t0; t++) {
double[][] samples =
Operations.sample_multivariate_normal(mu_hat_s.get(t), v_hat_s.get(t), N_SAMPLES);
double[][] h_t = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
h_t[i][k] = samples[i][k];
}
h_s.set(t, h_t);
}
/** impression feature * */
forward2(true);
backward2(true);
compute_gradient2(iter);
double new_obj_2 = 0;
/* gradient descent: inner for-loop here */
int inner_iter_2 = 0;
while (inner_iter_2 < INNER_ITER) {
/* update \hat{h}' using gradient descent */
for (int t = 0; t < T - t0; t++) {
double[][] h_hat_prime_t = h_hat_prime_s.get(t);
double[][] grad_h_hat_prime_t = grad_h_hat_prime_s.get(t);
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
h_hat_prime_t[i][k] += lr_2 * grad_h_hat_prime_t[i][k];
}
h_hat_prime_s.set(t, h_hat_prime_t);
}
/* update \hat{\mu}' and \hat{V}', since both are function of \hat{h}' */
forward2(false);
backward2(false);
double obj2 = compute_objective2();
if (inner_iter_2 % 10 == 0)
System.out.println("(2) iter = " + inner_iter_2 + ", obj 2 = " + obj2);
if (inner_iter_2 != 0 && obj2 < new_obj_2) {
lr_2 *= 0.8;
break;
}
new_obj_2 = obj2;
inner_iter_2 += 1;
}
if (inner_iter_2 == INNER_ITER) lr_2 *= 2;
/* sample */
for (int t = 0; t < T - t0; t++) {
double[][] samples =
Operations.sample_multivariate_normal(
mu_hat_prime_s.get(t), v_hat_prime_s.get(t), N_SAMPLES);
double[][] h_prime_t = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
h_prime_t[i][k] = samples[i][k];
}
h_prime_s.set(t, h_prime_t);
}
/** output * */
for (int t = 0; t < T - t0; t++) {
double[][] h_t = h_s.get(t);
double[][] h_prime_t = h_prime_s.get(t);
/* output filename:
* ./res/<seed>_<sigma>/h_<time>_<iter>.txt
*/
FileParser.output(
h_t, "./res/" + seed + "_" + delta_str + "/h_" + (t + t0) + "_" + iter + ".txt");
FileParser.output(
h_prime_t,
"./res/" + seed + "_" + delta_str + "/h_p_" + (t + t0) + "_" + iter + ".txt");
}
/* check convergence */
double diff_1 = -(new_obj_1 - old_obj_1) / old_obj_1;
double diff_2 = -(new_obj_2 - old_obj_2) / old_obj_2;
if (iter != 0 && diff_1 < 1e-6 && diff_2 < 1e-6) {
System.out.println("diff_1 = " + diff_1);
System.out.println("diff_2 = " + diff_2);
break;
}
old_obj_1 = new_obj_1;
old_obj_2 = new_obj_2;
}
}
/**
* forward pass 1: update intrinsic features (1) mu (mu_s) (2) grad_mu (grad_mu_s) (3) variance V
* (v_s)
*/
public static void forward1(boolean update_grad, int iter) {
/*
if (iter == 4) {
int t = 15;
double[][] h_t = new double[n][K];
double[][] h_hat_t = new double[n][K];
double[][] h_prime_t = new double[n][K];
double[][] h_hat_prime_t = new double[n][K];
for (int i = 0; i < n; i++) for (int k = 0; k < K; k++) {
h_t[i][k] = h_s.get(t-1)[i][k];
h_hat_t[i][k] = h_hat_s.get(t-1)[i][k];
h_prime_t[i][k] = h_prime_s.get(t-1)[i][k];
h_hat_prime_t[i][k] = h_hat_prime_s.get(t-1)[i][k];
}
h_s.set(t, h_t); h_hat_s.set(t, h_hat_t);
h_prime_s.set(t, h_prime_t); h_hat_prime_s.set(t, h_hat_prime_t);
}
*/
for (int t = 0; t < T - t0; t++) {
// System.out.println("forward 1;\tt = " + t1);
if (t != 0) {
double delta_t = delta_s.get(t); // delta_t
double[][] h_hat_t = h_hat_s.get(t); // \hat{h}^t [t]
double[][] mu_pre_t = mu_s.get(t - 1); // mu^{t-1} (N*1)
double V_pre_t = v_s.get(t - 1); // V^{t-1}
Matrix a = new Matrix(AS.get(t - 1)); // A^{t-1}
Matrix hprime_pre_t = new Matrix(h_prime_s.get(t - 1)); // h'^{t-1}
Matrix ave_neighbors = a.times(hprime_pre_t);
/* calculate \mu */
double[][] mu_t = new double[n][K];
double factor_1 =
(delta_t * delta_t)
/ (delta_t * delta_t + sigma * sigma + (1 - lambda) * (1 - lambda) * V_pre_t);
double factor_2 =
(sigma * sigma + (1 - lambda) * (1 - lambda) * V_pre_t)
/ (delta_t * delta_t + sigma * sigma + (1 - lambda) * (1 - lambda) * V_pre_t);
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
mu_t[i][k] =
factor_1 * ((1 - lambda) * mu_pre_t[i][k] + lambda * ave_neighbors.get(i, k))
+ factor_2 * h_hat_t[i][k];
}
/* calculate V */
double V_t = factor_2 * delta_t * delta_t;
/* update \mu and V */
mu_s.set(t, mu_t);
v_s.set(t, V_t);
/* calculate and update grad_mu */
if (update_grad)
for (int s = 0; s < T - t0; s++) {
double[][] grad_pre_t_s = grad_mu_s.get((t - 1) * (T - t0) + s);
double[][] grad_t_s = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
grad_t_s[i][k] = factor_1 * (1 - lambda) * grad_pre_t_s[i][k];
if (t == s) {
grad_t_s[i][k] += factor_2;
}
}
grad_mu_s.set(t * (T - t0) + s, grad_t_s);
}
} else {
/* mu, V: random init (keep unchanged) */
/* grad_mu: set to 0 (keep unchanged) */
}
// Scanner sc = new Scanner(System.in);
// int gu; gu = sc.nextInt();
/* end for each t */
}
}
public static void compute_gradient2(int iteration) {
double[][][] tmp_grad_h_hat_prime_s = new double[T - t0][n][K];
/*
* compute
* nti[t][i] = \sum_{j} { n_{ij} }
* and
* nti_h[t][j][k] = \sum_{i} { n_{ij}^{t} h_{ik}^{t} }
*/
double[][] nti = new double[T - t0][n];
double[][][] nti_h = new double[T - t0][n][K];
for (int t = 0; t < T - t0; t++) {
double[][] G_t = GS.get(t);
double[][] h_t = h_s.get(t); // h^{t}
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++) {
nti[t][i] += G_t[i][j];
for (int k = 0; k < K; k++) {
nti_h[t][j][k] += G_t[i][j] * h_t[i][k];
}
}
}
for (int t = 0; t < T - t0; t++) {
double delta_t = delta_prime_s.get(t);
double[][] h_t = h_s.get(t); // h^{t}
double[][] h_hat_prime_t = h_hat_prime_s.get(t); // \hat{h}^{t}
double[][] mu_hat_t = mu_hat_s.get(t); // \hat{\mu}^{t}
double[][] mu_hat_prime_t = mu_hat_prime_s.get(t); // \hat{\mu}'^{t}
double[][] h_prime_t = h_prime_s.get(t);
if (t != 0) {
Matrix a = new Matrix(AS.get(t - 1));
Matrix hprime_pre_t = new Matrix(h_prime_s.get(t - 1));
Matrix ave_neighbors = a.times(hprime_pre_t);
double[][] G_pre_t = GS.get(t - 1); // G^{t-1}
double[][] A_pre_t = AS.get(t - 1); // A^{t-1}
double[][] h_pre_t = h_s.get(t - 1); // h^{t-1}
double[][] mu_hat_prime_pre_t = mu_hat_prime_s.get(t - 1); // \hat{\mu}'^{t-1} [t]
for (int s = 0; s < T - t0; s++) {
double[][] grad_mu_hat_prime_t = grad_mu_hat_prime_s.get(t * (T - t0) + s);
double[][] grad_mu_hat_prime_pre_t = grad_mu_hat_prime_s.get((t - 1) * (T - t0) + s);
double[] h2delta2 = new double[n];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
h2delta2[i] += 0.5 * h_t[i][k] * h_t[i][k] * delta_t * delta_t;
}
/* compute weighted_exp for later use */
double[][][] weighted_exp_num = new double[K][n][n];
double[][] weighted_exp_den = new double[K][n];
double[][][] weighted_exp = new double[K][n][n];
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++) {
double h_muhp = Operations.inner_product(h_t[j], mu_hat_prime_t[i], K);
for (int k = 0; k < K; k++) {
weighted_exp_num[k][i][j] = h_t[j][k] * Math.exp(h_muhp + h2delta2[j]);
weighted_exp_den[k][j] += Math.exp(h_muhp + h2delta2[j]);
}
}
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
for (int k = 0; k < K; k++) {
weighted_exp[k][i][j] = weighted_exp_num[k][i][j] / weighted_exp_den[k][j];
}
/* compute sum_mu_hat_prime for later use */
double[] sum_mu_hat_prime = new double[K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
sum_mu_hat_prime[k] += mu_hat_prime_pre_t[i][k];
}
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
/* first term */
double g1 = nti_h[t][i][k] * grad_mu_hat_prime_t[i][k];
tmp_grad_h_hat_prime_s[s][i][k] += g1;
/* second term */
double g2 = 0;
for (int j = 0; j < n; j++) {
g2 -= nti[t][j] * weighted_exp[k][i][j] * grad_mu_hat_prime_t[i][k];
}
tmp_grad_h_hat_prime_s[s][i][k] += g2;
/* third term */
for (int j = 0; j < n; j++)
if (G_pre_t[j][i] != 0) {
// double g3 = ( h_t[j][k] - (1-lambda) * h_pre_t[j][k] - lambda *
// A_pre_t[j][i] * sum_mu_hat_prime[k] )
double g3 =
(h_t[j][k]
- (1 - lambda) * h_pre_t[j][k]
- lambda * A_pre_t[j][i] * mu_hat_prime_pre_t[i][k])
* lambda
* A_pre_t[j][i]
* grad_mu_hat_prime_pre_t[i][k]
/ (sigma * sigma);
tmp_grad_h_hat_prime_s[s][j][k] += g3; // j instead of i!
}
}
/* fourth term */
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
double g4 =
-(mu_hat_prime_t[i][k] - mu_hat_prime_pre_t[i][k])
* (grad_mu_hat_prime_t[i][k] - grad_mu_hat_prime_pre_t[i][k])
/ (sigma * sigma);
tmp_grad_h_hat_prime_s[s][i][k] += g4;
}
}
} else {
/*
for (int s = 0; s < T-t0; s++) {
double[] grad_mu_hat_prime_t = grad_mu_hat_prime_s.get(t * (T-t0) + s);
for (int i = 0; i < n; i++) {
// first term
double g1 = nti_hp[t][i] * grad_mu_hat_prime_t[i];
tmp_grad_h_hat_prime_s[s][i] += g1;
// second term
double g2 = 0;
for (int _j = 0; _j < NEG; _j++) {
double weighted_exp_num = 0, weighted_exp_den = 0;
int j = neg_samples.get(t)[i][_j];
double htj = h_t[j][0]; double muhti = mu_hat_t[i];
weighted_exp_num += htj * Math.exp(htj * muhti + 0.5 * htj * htj * delta_t * delta_t);
for (int _k = 0; _k < NEG; _k++) {
int k = neg_samples.get(t)[i][_k];
double muhtk = mu_hat_t[k];
weighted_exp_den += Math.exp(htj * muhtk + 0.5 * htj * htj * delta_t * delta_t);
}
g2 -= nti[t][j] * weighted_exp_num / weighted_exp_den * grad_mu_hat_prime_t[i];
}
tmp_grad_h_hat_prime_s[s][i] += g2;
}
// fourth term (if any)
if (s == t) for (int i = 0; i < n; i++) {
double g4 = -h_hat_prime_t[i][0] / (sigma*sigma);
tmp_grad_h_hat_prime_s[s][i] += g4;
}
}
*/
}
}
/* update global gradient */
for (int t = 0; t < T - t0; t++) {
double[][] grad = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
grad[i][k] = tmp_grad_h_hat_prime_s[t][i][k];
}
grad_h_hat_prime_s.set(t, grad);
}
FileParser.output_2d(grad_h_hat_prime_s, "./grad/grad_prime_" + iteration + ".txt");
return;
}
public static void compute_gradient1(int iteration) {
double[][][] tmp_grad_h_hat_s = new double[T - t0][n][K];
for (int t = 0; t < T - t0; t++) {
// System.out.println("compute gradient 1, t = " + t);
double delta_t = delta_s.get(t);
double[][] G_t = GS.get(t);
double[][] h_prime_t = h_prime_s.get(t);
double[][] mu_hat_t = mu_hat_s.get(t);
if (t != 0) {
double[][] mu_hat_pre_t = mu_hat_s.get(t - 1);
Matrix a = new Matrix(AS.get(t - 1));
Matrix hprime_pre_t = new Matrix(h_prime_s.get(t - 1));
Matrix ave_neighbors = a.times(hprime_pre_t);
/* TODO: check whether we can save computation by comparing s and t */
for (int s = 0; s < T - t0; s++) {
double[][] grad_hat_t = grad_mu_hat_s.get(t * (T - t0) + s);
double[][] grad_hat_pre_t = grad_mu_hat_s.get((t - 1) * (T - t0) + s);
double[] hp2delta2 = new double[n];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
hp2delta2[i] += 0.5 * h_prime_t[i][k] * h_prime_t[i][k] * delta_t * delta_t;
}
for (int i = 0; i < n; i++) {
/* first term */
double[] weighted_exp_num = new double[K];
double weighted_exp_den = 0;
for (int l = 0; l < n; l++) {
double hp_muh = Operations.inner_product(h_prime_t[l], mu_hat_t[i], K);
double e = Math.exp(hp_muh + hp2delta2[l]);
if (Double.isNaN(e)) {
/* check if e explodes */
System.out.println("ERROR2");
Scanner sc = new Scanner(System.in);
int gu;
gu = sc.nextInt();
}
for (int k = 0; k < K; k++) {
weighted_exp_num[k] += h_prime_t[l][k] * e;
weighted_exp_den += e;
}
}
for (int j = 0; j < n; j++)
for (int k = 0; k < K; k++) {
double weighted_exp = weighted_exp_num[k] / weighted_exp_den;
double gi1 = G_t[i][j] * grad_hat_t[i][k] * (h_prime_t[j][k] - weighted_exp);
tmp_grad_h_hat_s[s][i][k] += gi1;
}
/* second term */
for (int k = 0; k < K; k++) {
double gi2 =
-(mu_hat_t[i][k]
- (1 - lambda) * mu_hat_pre_t[i][k]
- lambda * ave_neighbors.get(i, k))
* (grad_hat_t[i][k] - (1 - lambda) * grad_hat_pre_t[i][k])
/ (sigma * sigma);
tmp_grad_h_hat_s[s][i][k] += gi2;
}
}
}
} else {
/* no such term (t=0) in ELBO */
/*
for (int s = 0; s < T-t0; s++) {
double[] grad_hat_t = grad_mu_hat_s.get(t * (T-t0) + s);
for (int i = 0; i < n; i++) {
double n_it = 0;
for (int j = 0; j < n; j++) n_it += G_t[i][j];
// first term
double gi1 = -mu_hat_t[i] * grad_hat_t[i] / (sigma * sigma);
tmp_grad_h_hat_s[s][i] += gi1;
// second term
double gi2 = 0;
double weighted_exp_num = 0, weighted_exp_den = 0;
for (int j = 0; j < NEG; j++) {
int l = neg_samples.get(t)[i][j];
double hpl = h_prime_t[l][0];
double muit = mu_hat_t[i];
double e = Math.exp(hpl * muit + 0.5 * hpl * hpl * delta_t * delta_t);
// TODO: check if e explodes
if (Double.isNaN(e)) {
System.out.println("ERROR3");
Scanner sc = new Scanner(System.in);
int gu; gu = sc.nextInt();
}
weighted_exp_num += hpl * e;
weighted_exp_den += e;
}
double weighted_exp = weighted_exp_num / weighted_exp_den;
for (int j = 0; j < n; j++) {
gi2 += G_t[i][j] * grad_hat_t[i] * (h_prime_t[j][0] - weighted_exp);
}
tmp_grad_h_hat_s[s][i] += gi2;
}
}
*/
}
/* end if-else */
}
/* update global gradient */
for (int t = 0; t < T - t0; t++) {
double[][] grad = new double[n][K];
for (int i = 0; i < n; i++)
for (int k = 0; k < K; k++) {
grad[i][k] = tmp_grad_h_hat_s[t][i][k];
}
grad_h_hat_s.set(t, grad);
}
FileParser.output_2d(grad_h_hat_s, "./grad/grad_" + iteration + ".txt");
return;
}