# PNN¶

Reference:

Qu Y et al. “Product-based neural networks for user response prediction.” in ICDM 2016

Reference code:
class recbole.model.context_aware_recommender.pnn.InnerProductLayer(num_feature_field, device)[source]

Bases: torch.nn.modules.module.Module

InnerProduct Layer used in PNN that compute the element-wise product or inner product between feature vectors.

forward(feat_emb)[source]
Parameters

feat_emb (torch.FloatTensor) – 3D tensor with shape: [batch_size,num_pairs,embedding_size].

Returns

The inner product of input tensor. shape of [batch_size, num_pairs]

Return type

inner_product(torch.FloatTensor)

training: bool
class recbole.model.context_aware_recommender.pnn.OuterProductLayer(num_feature_field, embedding_size, device)[source]

Bases: torch.nn.modules.module.Module

OuterProduct Layer used in PNN. This implementation is adapted from code that the author of the paper published on https://github.com/Atomu2014/product-nets.

forward(feat_emb)[source]
Parameters

feat_emb (torch.FloatTensor) – 3D tensor with shape: [batch_size,num_pairs,embedding_size].

Returns

The outer product of input tensor. shape of [batch_size, num_pairs]

Return type

outer_product(torch.FloatTensor)

training: bool
class recbole.model.context_aware_recommender.pnn.PNN(config, dataset)[source]

PNN calculate inner and outer product of feature embedding. You can choose the product option with the parameter of use_inner and use_outer

calculate_loss(interaction)[source]

Calculate the training loss for a batch data.

Parameters

interaction (Interaction) – Interaction class of the batch.

Returns

Training loss, shape: []

Return type

torch.Tensor

forward(interaction)[source]

Defines the computation performed at every call.

Should be overridden by all subclasses.

Note

Although the recipe for forward pass needs to be defined within this function, one should call the Module instance afterwards instead of this since the former takes care of running the registered hooks while the latter silently ignores them.

predict(interaction)[source]

Predict the scores between users and items.

Parameters

interaction (Interaction) – Interaction class of the batch.

Returns

Predicted scores for given users and items, shape: [batch_size]

Return type

torch.Tensor

reg_loss()[source]

Calculate the L2 normalization loss of model parameters. Including weight matrices of mlp layers.

Returns

The L2 Loss tensor. shape of [1,]

Return type

loss(torch.FloatTensor)

training: bool