def build()

in easy_rec/python/builders/loss_builder.py [0:0]


def build(loss_type,
          label,
          pred,
          loss_weight=1.0,
          num_class=1,
          loss_param=None,
          **kwargs):
  loss_name = kwargs.pop('loss_name') if 'loss_name' in kwargs else 'unknown'
  if loss_type == LossType.CLASSIFICATION:
    if num_class == 1:
      return tf.losses.sigmoid_cross_entropy(
          label, logits=pred, weights=loss_weight, **kwargs)
    else:
      assert label.dtype in [tf.int32, tf.int64], \
          'label.dtype must in [tf.int32, tf.int64] when use sparse_softmax_cross_entropy.'
      return tf.losses.sparse_softmax_cross_entropy(
          labels=label, logits=pred, weights=loss_weight, **kwargs)
  elif loss_type == LossType.CROSS_ENTROPY_LOSS:
    return tf.losses.log_loss(label, pred, weights=loss_weight, **kwargs)
  elif loss_type == LossType.BINARY_CROSS_ENTROPY_LOSS:
    losses = tf.keras.backend.binary_crossentropy(label, pred, from_logits=True)
    return tf.reduce_mean(losses)
  elif loss_type in [LossType.L2_LOSS, LossType.SIGMOID_L2_LOSS]:
    logging.info('%s is used' % LossType.Name(loss_type))
    return tf.losses.mean_squared_error(
        labels=label, predictions=pred, weights=loss_weight, **kwargs)
  elif loss_type == LossType.ZILN_LOSS:
    loss = zero_inflated_lognormal_loss(label, pred)
    if np.isscalar(loss_weight) and loss_weight != 1.0:
      return loss * loss_weight
    return loss
  elif loss_type == LossType.JRC_LOSS:
    session = kwargs.get('session_ids', None)
    if loss_param is None:
      return jrc_loss(label, pred, session, name=loss_name)
    return jrc_loss(
        label,
        pred,
        session,
        loss_param.alpha,
        loss_weight_strategy=loss_param.loss_weight_strategy,
        sample_weights=loss_weight,
        same_label_loss=loss_param.same_label_loss,
        name=loss_name)
  elif loss_type == LossType.PAIR_WISE_LOSS:
    session = kwargs.get('session_ids', None)
    margin = 0 if loss_param is None else loss_param.margin
    temp = 1.0 if loss_param is None else loss_param.temperature
    return pairwise_loss(
        label,
        pred,
        session_ids=session,
        margin=margin,
        temperature=temp,
        weights=loss_weight,
        name=loss_name)
  elif loss_type == LossType.PAIRWISE_LOGISTIC_LOSS:
    session = kwargs.get('session_ids', None)
    temp = 1.0 if loss_param is None else loss_param.temperature
    ohem_ratio = 1.0 if loss_param is None else loss_param.ohem_ratio
    hinge_margin = None
    if loss_param is not None and loss_param.HasField('hinge_margin'):
      hinge_margin = loss_param.hinge_margin
    lbl_margin = False if loss_param is None else loss_param.use_label_margin
    return pairwise_logistic_loss(
        label,
        pred,
        session_ids=session,
        temperature=temp,
        hinge_margin=hinge_margin,
        ohem_ratio=ohem_ratio,
        weights=loss_weight,
        use_label_margin=lbl_margin,
        name=loss_name)
  elif loss_type == LossType.PAIRWISE_HINGE_LOSS:
    session = kwargs.get('session_ids', None)
    temp, ohem_ratio, margin = 1.0, 1.0, 1.0
    label_is_logits, use_label_margin, use_exponent = True, True, False
    if loss_param is not None:
      temp = loss_param.temperature
      ohem_ratio = loss_param.ohem_ratio
      margin = loss_param.margin
      label_is_logits = loss_param.label_is_logits
      use_label_margin = loss_param.use_label_margin
      use_exponent = loss_param.use_exponent
    return pairwise_hinge_loss(
        label,
        pred,
        session_ids=session,
        temperature=temp,
        margin=margin,
        ohem_ratio=ohem_ratio,
        weights=loss_weight,
        label_is_logits=label_is_logits,
        use_label_margin=use_label_margin,
        use_exponent=use_exponent,
        name=loss_name)
  elif loss_type == LossType.PAIRWISE_FOCAL_LOSS:
    session = kwargs.get('session_ids', None)
    if loss_param is None:
      return pairwise_focal_loss(
          label, pred, session_ids=session, weights=loss_weight, name=loss_name)
    hinge_margin = None
    if loss_param.HasField('hinge_margin'):
      hinge_margin = loss_param.hinge_margin
    return pairwise_focal_loss(
        label,
        pred,
        session_ids=session,
        gamma=loss_param.gamma,
        alpha=loss_param.alpha if loss_param.HasField('alpha') else None,
        hinge_margin=hinge_margin,
        ohem_ratio=loss_param.ohem_ratio,
        temperature=loss_param.temperature,
        weights=loss_weight,
        name=loss_name)
  elif loss_type == LossType.LISTWISE_RANK_LOSS:
    session = kwargs.get('session_ids', None)
    trans_fn, temp, label_is_logits, scale = None, 1.0, False, False
    if loss_param is not None:
      temp = loss_param.temperature
      label_is_logits = loss_param.label_is_logits
      scale = loss_param.scale_logits
      if loss_param.HasField('transform_fn'):
        trans_fn = loss_param.transform_fn
    return listwise_rank_loss(
        label,
        pred,
        session,
        temperature=temp,
        label_is_logits=label_is_logits,
        transform_fn=trans_fn,
        scale_logits=scale,
        weights=loss_weight)
  elif loss_type == LossType.LISTWISE_DISTILL_LOSS:
    session = kwargs.get('session_ids', None)
    trans_fn, temp, label_clip_max_value, scale = None, 1.0, 512.0, False
    if loss_param is not None:
      temp = loss_param.temperature
      label_clip_max_value = loss_param.label_clip_max_value
      scale = loss_param.scale_logits
      if loss_param.HasField('transform_fn'):
        trans_fn = loss_param.transform_fn
    return listwise_distill_loss(
        label,
        pred,
        session,
        temperature=temp,
        label_clip_max_value=label_clip_max_value,
        transform_fn=trans_fn,
        scale_logits=scale,
        weights=loss_weight)
  elif loss_type == LossType.F1_REWEIGHTED_LOSS:
    f1_beta_square = 1.0 if loss_param is None else loss_param.f1_beta_square
    label_smoothing = 0 if loss_param is None else loss_param.label_smoothing
    return f1_reweight_sigmoid_cross_entropy(
        label,
        pred,
        f1_beta_square,
        weights=loss_weight,
        label_smoothing=label_smoothing)
  elif loss_type == LossType.BINARY_FOCAL_LOSS:
    if loss_param is None:
      return sigmoid_focal_loss_with_logits(
          label, pred, sample_weights=loss_weight, name=loss_name)
    gamma = loss_param.gamma
    alpha = None
    if loss_param.HasField('alpha'):
      alpha = loss_param.alpha
    return sigmoid_focal_loss_with_logits(
        label,
        pred,
        gamma=gamma,
        alpha=alpha,
        ohem_ratio=loss_param.ohem_ratio,
        sample_weights=loss_weight,
        label_smoothing=loss_param.label_smoothing,
        name=loss_name)
  else:
    raise ValueError('unsupported loss type: %s' % LossType.Name(loss_type))