private void getnegphase() { /* * It does the negative phase of unsupervised RBM training algorithm * * For details, please refer to Dr. Hinton's paper: * Reducing the dimensionality of data with neural networks. Science, Vol. 313. no. 5786, pp. 504 - 507, 28 July 2006. */ // start calculate the negative phase // calculate the curved value of v1,h1 // find the vector of v1 Matrix negdata = poshidstates.times(vishid.transpose()); // (1 * numhid) * (numhid * numdims) = (1 * numdims) negdata.plusEquals(visbiases); // poshidstates*vishid' + visbiases double[][] tmp1 = negdata.getArray(); int i1 = 0; while (i1 < numdims) { tmp1[0][i1] = 1 / (1 + Math.exp(-tmp1[0][i1])); i1++; } // find the vector of h1 neghidprobs = negdata.times(vishid); // (1 * numdims) * (numdims * numhid) = (1 * numhid) neghidprobs.plusEquals(hidbiases); double[][] tmp2 = neghidprobs.getArray(); int i2 = 0; while (i2 < numhid) { tmp2[0][i2] = 1 / (1 + Math.exp(-tmp2[0][i2])); i2++; } negprods = negdata.transpose().times(neghidprobs); // (numdims * 1) *(1 * numhid) = (numdims * numhid) }
private void prop2nextLayer() { /* * It computes the forward propagation algorithm. */ poshidprobs = data.times(vishid); // (1 * numdims) * (numdims * numhid) poshidprobs.plusEquals(hidbiases); // data*vishid + hidbiases double[][] product_tmp2 = poshidprobs.getArray(); for (int i2 = 0; i2 < numhid; i2++) { /* * compute the updated input, and write them to newinput */ product_tmp2[0][i2] = 1 / (1 + Math.exp(-product_tmp2[0][i2])); newinput[i2] = (int) (product_tmp2[0][i2] * 255.0); } }
/** toy example */ public static void test2() { int N = 500; double[][] m1 = new double[N][N]; double[][] m2 = new double[N][N]; double[][] m3 = new double[N][N]; // init Random rand = new Random(); for (int i = 0; i < N; i++) for (int j = 0; j < N; j++) { m1[i][j] = 10 * (rand.nextDouble() - 0.2); m2[i][j] = 20 * (rand.nextDouble() - 0.8); } // inverse System.out.println("Start"); Matrix mat1 = new Matrix(m1); Matrix mat2 = mat1.inverse(); Matrix mat3 = mat1.times(mat2); double[][] m4 = mat3.getArray(); /* for (int i = 0; i < m4.length; i++) { int ss = 10; for (int j = 0; j < ss; j++) { System.out.printf("%f ", m4[i][j]); } System.out.print("\n"); } */ System.out.println("Done"); /* // matrix * System.out.println("Start"); for (int i = 0; i < N; i++) for (int j = 0; j < N; j++) { double cell = 0; for (int k = 0; k < N; k++) cell += m1[i][k] * m2[k][j]; // System.out.printf("%f ", cell); m3[i][j] = cell; } System.out.println("Done"); */ }
private void getposphase() { /* * It does the positive phase of unsupervised RBM training algorithm * * For details, please refer to Dr. Hinton's paper: * Reducing the dimensionality of data with neural networks. Science, Vol. 313. no. 5786, pp. 504 - 507, 28 July 2006. */ // Start calculate the positive phase // calculate the cured value of h0 poshidprobs = data.times(vishid); // (1 * numdims) * (numdims * numhid) poshidprobs.plusEquals(hidbiases); // data*vishid + hidbiases double[][] product_tmp2 = poshidprobs.getArray(); int i2 = 0; while (i2 < numhid) { product_tmp2[0][i2] = 1 / (1 + Math.exp(-product_tmp2[0][i2])); i2++; } posprods = data.transpose().times(poshidprobs); // (numdims * 1) * (1 * numhid) // end of the positive phase calculation, find the binary presentation of h0 int i3 = 0; double[][] tmp1 = poshidprobs.getArray(); double[][] tmp2 = new double[1][numhid]; Random randomgenerator = new Random(); while (i3 < numhid) { /* * a sampling according to possiblity given by poshidprobs */ if (tmp1[0][i3] > randomgenerator.nextDouble()) tmp2[0][i3] = 1; else tmp2[0][i3] = 0; i3++; } // poshidstates is a binary sampling according to possiblity given by poshidprobs poshidstates = new Matrix(tmp2); }
// update the weights and biases // This serves as a reducer private void update() { /* * It computes the update of weights using previous results and parameters * * For details, please refer to Dr. Hinton's paper: * Reducing the dimensionality of data with neural networks. Science, Vol. 313. no. 5786, pp. 504 - 507, 28 July 2006. */ double momentum; // if (epoch > 5) // momentum = finalmomentum; // else // momentum = initialmomentum; // vishidinc = momentum*vishidinc + epsilonw*( (posprods-negprods)/numcases - // weightcost*vishid); // vishidinc.timesEquals(momentum); Matrix temp1 = posprods.minus(negprods); Matrix temp2 = vishid.times(weightcost); temp1.minusEquals(temp2); temp1.timesEquals(epsilonw); // the final updates of weights are written in vishidinc vishidinc.plusEquals(temp1); }
/* * 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 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; }
/** compute_objective1: return the lower bound when h' is fixed */ public static double compute_objective1() { double res = 0; for (int t = 0; t < T - t0; t++) { if (t != 0) { double[][] G_t = GS.get(t); double[][] h_prime_t = h_prime_s.get(t); double[][] h_prime_pre_t = h_prime_s.get(t - 1); double[][] mu_hat_t = mu_hat_s.get(t); double[][] mu_hat_pre_t = mu_hat_s.get(t - 1); double delta_t = delta_s.get(t); 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[] 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 */ List<Double> powers = new ArrayList<Double>(); for (int l = 0; l < n; l++) { double hp_muh = Operations.inner_product(h_prime_t[l], mu_hat_t[i], K); powers.add(hp_muh + hp2delta2[l]); } double lse = log_sum_exp(powers); for (int j = 0; j < n; j++) if (G_t[i][j] != 0) { double hp_muh = Operations.inner_product(h_prime_t[j], mu_hat_t[i], K); res += G_t[i][j] * (hp_muh - lse); } /* second term */ for (int k = 0; k < K; k++) { double diff = mu_hat_t[i][k] - (1 - lambda) * mu_hat_pre_t[i][k] - lambda * ave_neighbors.get(i, k); res -= 0.5 * diff * diff / (sigma * sigma); } } } else { /* double[][] G_t = GS.get(t); double[][] h_prime_t = h_prime_s.get(t); double[] mu_hat_t = mu_hat_s.get(t); double delta_t = delta_s.get(t); int[][] neg_sam_t = neg_samples.get(t); for (int i = 0; i < n; i++) { // first term for (int j = 0; j < n; j++) if (G_t[i][j] != 0) { List<Double> powers = new ArrayList<Double>(); for (int _l = 0; _l < NEG; _l++) { int l = neg_sam_t[i][_l]; powers.add(h_prime_t[l][0] * mu_hat_t[i] + 0.5 * h_prime_t[l][0] * h_prime_t[l][0] * delta_t * delta_t); } double lse = log_sum_exp(powers); res += G_t[i][j] * (h_prime_t[j][0] * mu_hat_t[i] - lse); } } */ } } return res; }