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#!/usr/bin/env python |
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# -*- coding: utf-8 -*- |
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import os |
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import numpy as np |
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from numpy import linalg as LA |
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from theano import tensor as T |
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import theano |
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from theano.tensor.shared_randomstreams import RandomStreams |
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from deepy import NeuralClassifier |
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from deepy.utils import build_activation, disconnected_grad |
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from deepy.utils.functions import FLOATX |
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from deepy.layers import NeuralLayer |
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from experiments.attention_models.gaussian_sampler import SampleMultivariateGaussian |
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class AttentionLayer(NeuralLayer): |
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def __init__(self, activation='relu', std=0.1, disable_reinforce=False, random_glimpse=False): |
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self.disable_reinforce = disable_reinforce |
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self.random_glimpse = random_glimpse |
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self.gaussian_std = std |
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super(AttentionLayer, self).__init__(10, activation) |
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def initialize(self, config, vars, x, input_n, id="UNKNOWN"): |
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self._config = config |
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self._vars = vars |
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self.input_n = input_n |
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self.id = id |
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self.x = x |
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self._setup_params() |
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self._setup_functions() |
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self.connected = True |
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def _glimpse_sensor(self, x_t, l_p): |
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""" |
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Parameters: |
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x_t - 28x28 image |
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l_p - 2x1 focus vector |
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Returns: |
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4x12 matrix |
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""" |
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# Turn l_p to the left-top point of rectangle |
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l_p = l_p * 14 + 14 - 2 |
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l_p = T.cast(T.round(l_p), "int32") |
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l_p = l_p * (l_p >= 0) |
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l_p = l_p * (l_p < 24) + (l_p >= 24) * 23 |
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l_p2 = l_p - 2 |
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l_p2 = l_p2 * (l_p2 >= 0) |
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l_p2 = l_p2 * (l_p2 < 20) + (l_p2 >= 20) * 19 |
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l_p3 = l_p - 6 |
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l_p3 = l_p3 * (l_p3 >= 0) |
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l_p3 = l_p3 * (l_p3 < 16) + (l_p3 >= 16) * 15 |
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glimpse_1 = x_t[l_p[0]: l_p[0] + 4][:, l_p[1]: l_p[1] + 4] |
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glimpse_2 = x_t[l_p2[0]: l_p2[0] + 8][:, l_p2[1]: l_p2[1] + 8] |
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glimpse_2 = theano.tensor.signal.downsample.max_pool_2d(glimpse_2, (2,2)) |
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glimpse_3 = x_t[l_p3[0]: l_p3[0] + 16][:, l_p3[1]: l_p3[1] + 16] |
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glimpse_3 = theano.tensor.signal.downsample.max_pool_2d(glimpse_3, (4,4)) |
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return T.concatenate([glimpse_1, glimpse_2, glimpse_3]) |
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View Code Duplication |
def _refined_glimpse_sensor(self, x_t, l_p): |
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""" |
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Parameters: |
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x_t - 28x28 image |
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l_p - 2x1 focus vector |
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Returns: |
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7*14 matrix |
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""" |
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# Turn l_p to the left-top point of rectangle |
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l_p = l_p * 14 + 14 - 4 |
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l_p = T.cast(T.round(l_p), "int32") |
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l_p = l_p * (l_p >= 0) |
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l_p = l_p * (l_p < 21) + (l_p >= 21) * 20 |
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glimpse_1 = x_t[l_p[0]: l_p[0] + 7][:, l_p[1]: l_p[1] + 7] |
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# glimpse_2 = theano.tensor.signal.downsample.max_pool_2d(x_t, (4,4)) |
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# return T.concatenate([glimpse_1, glimpse_2]) |
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return glimpse_1 |
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def _multi_gaussian_pdf(self, vec, mean): |
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norm2d_var = ((1.0 / T.sqrt((2*np.pi)**2 * self.cov_det_var)) * |
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T.exp(-0.5 * ((vec-mean).T.dot(self.cov_inv_var).dot(vec-mean)))) |
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return norm2d_var |
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def _glimpse_network(self, x_t, l_p): |
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""" |
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Parameters: |
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x_t - 28x28 image |
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l_p - 2x1 focus vector |
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Returns: |
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4x12 matrix |
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""" |
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sensor_output = self._refined_glimpse_sensor(x_t, l_p) |
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sensor_output = T.flatten(sensor_output) |
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h_g = self._relu(T.dot(sensor_output, self.W_g0)) |
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h_l = self._relu(T.dot(l_p, self.W_g1)) |
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g = self._relu(T.dot(h_g, self.W_g2_hg) + T.dot(h_l, self.W_g2_hl)) |
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return g |
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def _location_network(self, h_t): |
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""" |
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Parameters: |
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h_t - 256x1 vector |
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Returns: |
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2x1 focus vector |
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""" |
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return T.dot(h_t, self.W_l) |
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def _action_network(self, h_t): |
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""" |
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Parameters: |
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h_t - 256x1 vector |
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Returns: |
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10x1 vector |
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""" |
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z = self._relu(T.dot(h_t, self.W_a) + self.B_a) |
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return self._softmax(z) |
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View Code Duplication |
def _core_network(self, l_p, h_p, x_t): |
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""" |
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Parameters: |
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x_t - 28x28 image |
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l_p - 2x1 focus vector |
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h_p - 256x1 vector |
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Returns: |
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h_t, 256x1 vector |
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""" |
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g_t = self._glimpse_network(x_t, l_p) |
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h_t = self._tanh(T.dot(g_t, self.W_h_g) + T.dot(h_p, self.W_h) + self.B_h) |
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l_t = self._location_network(h_t) |
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if not self.disable_reinforce: |
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sampled_l_t = self._sample_gaussian(l_t, self.cov) |
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sampled_pdf = self._multi_gaussian_pdf(disconnected_grad(sampled_l_t), l_t) |
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wl_grad = T.grad(T.log(sampled_pdf), self.W_l) |
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else: |
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sampled_l_t = l_t |
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wl_grad = self.W_l |
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if self.random_glimpse and self.disable_reinforce: |
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sampled_l_t = self.srng.uniform((2,)) * 0.8 |
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a_t = self._action_network(h_t) |
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return sampled_l_t, h_t, a_t, wl_grad |
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View Code Duplication |
def _output_func(self): |
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self.x = self.x.reshape((28, 28)) |
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[l_ts, h_ts, a_ts, wl_grads], _ = theano.scan(fn=self._core_network, |
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outputs_info=[self.l0, self.h0, None, None], |
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non_sequences=[self.x], |
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n_steps=5) |
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self.positions = l_ts |
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self.last_decision = T.argmax(a_ts[-1]) |
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wl_grad = T.sum(wl_grads, axis=0) / wl_grads.shape[0] |
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self.wl_grad = wl_grad |
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return a_ts[-1].reshape((1,10)) |
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def _setup_functions(self): |
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self._assistive_params = [] |
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self._relu = build_activation("tanh") |
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self._tanh = build_activation("tanh") |
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self._softmax = build_activation("softmax") |
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self.output_func = self._output_func() |
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View Code Duplication |
def _setup_params(self): |
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self.srng = RandomStreams(seed=234) |
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self.large_cov = np.array([[0.06,0],[0,0.06]], dtype=FLOATX) |
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self.small_cov = np.array([[self.gaussian_std,0],[0,self.gaussian_std]], dtype=FLOATX) |
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self.cov = theano.shared(np.array(self.small_cov, dtype=FLOATX)) |
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self.cov_inv_var = theano.shared(np.array(LA.inv(self.small_cov), dtype=FLOATX)) |
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self.cov_det_var = theano.shared(np.array(LA.det(self.small_cov), dtype=FLOATX)) |
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self._sample_gaussian = SampleMultivariateGaussian() |
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self.W_g0 = self.create_weight(7*7, 128, suffix="g0") |
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self.W_g1 = self.create_weight(2, 128, suffix="g1") |
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self.W_g2_hg = self.create_weight(128, 256, suffix="g2_hg") |
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self.W_g2_hl = self.create_weight(128, 256, suffix="g2_hl") |
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self.W_h_g = self.create_weight(256, 256, suffix="h_g") |
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self.W_h = self.create_weight(256, 256, suffix="h") |
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self.B_h = self.create_bias(256, suffix="h") |
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self.h0 = self.create_vector(256, "h0") |
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self.l0 = self.create_vector(2, "l0") |
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self.l0.set_value(np.array([-1, -1], dtype=FLOATX)) |
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self.W_l = self.create_weight(256, 2, suffix="l") |
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self.W_l.set_value(self.W_l.get_value() / 10) |
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self.B_l = self.create_bias(2, suffix="l") |
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self.W_a = self.create_weight(256, 10, suffix="a") |
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self.B_a = self.create_bias(10, suffix="a") |
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self.W = [self.W_g0, self.W_g1, self.W_g2_hg, self.W_g2_hl, self.W_h_g, self.W_h, self.W_a] |
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self.B = [self.B_h, self.B_a] |
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self.parameters = [self.W_l] |
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def get_network(model=None, std=0.005, disable_reinforce=False, random_glimpse=False): |
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""" |
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Get baseline model. |
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Parameters: |
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model - model path |
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Returns: |
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network |
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""" |
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network = NeuralClassifier(input_dim=28 * 28) |
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network.stack_layer(AttentionLayer(std=std, disable_reinforce=disable_reinforce, random_glimpse=random_glimpse)) |
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if model and os.path.exists(model): |
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network.load_params(model) |
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return network |
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