com.expleague.ml.models.nn.nodes.PoolNode Maven / Gradle / Ivy
package com.expleague.ml.models.nn.nodes;
import com.expleague.commons.math.vectors.Vec;
import com.expleague.ml.models.nn.NeuralSpider.BackwardNode;
import com.expleague.ml.models.nn.NeuralSpider.ForwardNode;
import com.expleague.ml.models.nn.layers.Layer;
public class PoolNode implements Layer.Node {
private final int layerStart;
private final int prevLayerStart;
private final int numInputChannels;
private final int prevWidth;
private final int width;
private final int height;
private final int kSizeX;
private final int kSizeY;
private final int strideX;
private final int strideY;
public PoolNode(int layerStart, int prevLayerStart, int numInputChannels,
int prevWidth, int width, int height,
int kSizeX, int kSizeY, int strideX, int strideY) {
this.layerStart = layerStart;
this.prevLayerStart = prevLayerStart;
this.numInputChannels = numInputChannels;
this.prevWidth = prevWidth;
this.width = width;
this.height = height;
this.kSizeX = kSizeX;
this.kSizeY = kSizeY;
this.strideX = strideX;
this.strideY = strideY;
}
@Override
public ForwardNode forward() {
return new ForwardCalcer();
}
@Override
public BackwardNode backward() {
return new BackwardCalcer();
}
@Override
public BackwardNode gradient() {
return new BackwardNode.Stub();
}
private class ForwardCalcer implements ForwardNode {
private volatile Vec cachedState;
@Override
public double apply(Vec state, Vec betta, int nodeIdx) {
if (cachedState == null) {
cachedState = state;
}
final int localIdx = nodeIdx - layerStart;
final int c_out = localIdx % numInputChannels;
final int y_out = (localIdx / numInputChannels) % width;
final int x_out = localIdx / numInputChannels / width;
final int y = y_out * strideY;
final int x = x_out * strideX;
double result = Double.NEGATIVE_INFINITY;
int bestIdx = 0;
for (int i = 0; i < kSizeX; i++) {
for (int j = 0; j < kSizeY; j++) {
final int idx = prevLayerStart + ((x + i) * prevWidth + (y + j)) * numInputChannels + c_out;
final double value = state.get(idx);
if (value > result) {
result = value;
bestIdx = idx;
}
}
}
return bestIdx;
}
@Override
public double activate(double value) {
return cachedState.get((int) value);
}
@Override
public double grad(double value) {
return value;
}
private int getX(int nodeIdx) {
final int localIdx = nodeIdx - layerStart;
final int x_out = localIdx / numInputChannels / width;
return x_out * strideX;
}
@Override
public int start(int nodeIdx) {
return prevLayerStart + getX(nodeIdx) * prevWidth * numInputChannels;
}
@Override
public int end(int nodeIdx) {
final int endX = getX(nodeIdx) + kSizeX;
return prevLayerStart + endX * prevWidth * numInputChannels;
}
}
private class BackwardCalcer implements BackwardNode {
@Override
public double apply(Vec state, Vec gradState, Vec gradAct, Vec betta, int nodeIdx) {
final int localIdx = nodeIdx - prevLayerStart;
final int i = localIdx / numInputChannels / prevWidth;
final int j = (localIdx / numInputChannels) % prevWidth;
final int k = localIdx % numInputChannels;
double result = 0.;
final int minX = Math.max(((i - kSizeX) / strideX), 0);
final int minY = Math.max(((j - kSizeY) / strideY), 0);
final int maxX = Math.min((i / strideX), height);
final int maxY = Math.min((j / strideY), width);
if (minX >= height || minY >= width) {
return 0.;
}
for (int x_out = minX; x_out <= maxX; x_out++) {
for (int y_out = minY; y_out <= maxY; y_out++) {
final int x = x_out * strideX;
final int y = y_out * strideY;
if (x < i - kSizeX + 1 || x > i || y < j - kSizeY + 1 || y > j) {
continue;
}
if (x_out >= height || y_out >= width) {
continue;
}
final int stateIdx = layerStart + (x_out * width + y_out) * numInputChannels + k;
final int prevStateIdx = prevLayerStart + (x * prevWidth + y) * numInputChannels + k;
final int index = (int) gradAct.get(stateIdx);
if (index == nodeIdx) {
result += gradState.get(stateIdx);
}
}
}
return result;
}
private int getX(int nodeIdx) {
final int localIdx = nodeIdx - prevLayerStart;
final int i = localIdx / numInputChannels / prevWidth;
return (i - kSizeX + 1) / strideX;
}
@Override
public int start(int nodeIdx) {
return layerStart + getX(nodeIdx) * width * numInputChannels;
}
@Override
public int end(int nodeIdx) {
final int endX = getX(nodeIdx) + kSizeX;
return layerStart + endX * width * numInputChannels;
}
}
}
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