nextBatch method

Map<String, Float32List> nextBatch(int batchSize)

Implementation

Map<String, Float32List> nextBatch(int batchSize) {
  final int features = imageSize * imageSize * 3;
  final anchorBatch = Float32List(batchSize * features);
  final positiveBatch = Float32List(batchSize * features);
  final negativeBatch = Float32List(batchSize * features);

  final people = _identityMap.keys.toList();

  for (int i = 0; i < batchSize; i++) {
    // 1. Pick Anchor/Positive
    final personA = people[_random.nextInt(people.length)];
    final imagesA = _identityMap[personA]!;

    final idx1 = _random.nextInt(imagesA.length);
    int idx2 = _random.nextInt(imagesA.length);
    if (imagesA.length > 1) {
      while (idx1 == idx2) {
        idx2 = _random.nextInt(imagesA.length);
      }
    }

    // 2. Pick Negative
    String personB;
    do {
      personB = people[_random.nextInt(people.length)];
    } while (personA == personB);
    final imagesB = _identityMap[personB]!;
    final idx3 = _random.nextInt(imagesB.length);

    // 3. Set pixel data into the batch lists (Types now match: Float32List to Float32List)
    anchorBatch.setAll(i * features, imagesA[idx1]);
    positiveBatch.setAll(i * features, imagesA[idx2]);
    negativeBatch.setAll(i * features, imagesB[idx3]);
  }

  return {
    'anchor': anchorBatch,
    'positive': positiveBatch,
    'negative': negativeBatch,
  };
}