ai.libs.jaicore.ml.dyadranking.algorithm

Class PLNetLoss

java.lang.Object

ai.libs.jaicore.ml.dyadranking.algorithm.PLNetLoss

public class PLNetLoss
extends java.lang.Object

Implements the negative log likelihood (NLL) loss function for PL networks as described in [1]. * [1]: Dirk Schäfer, Eyke Hüllermeier (2018). Dyad ranking using Plackett-Luce models based on joint feature representations

Method Summary

Modifier and Type	Method and Description
static org.nd4j.linalg.api.ndarray.INDArray	computeLoss(org.nd4j.linalg.api.ndarray.INDArray plNetOutputs) Computes the NLL for PL networks according to equation (27) in [1].
static org.nd4j.linalg.api.ndarray.INDArray	computeLossGradient(org.nd4j.linalg.api.ndarray.INDArray plNetOutputs, int k) Computes the gradient of the NLL for PL networks w.r.t. the k-th dyad according to equation (28) in [1].

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

computeLoss

public static org.nd4j.linalg.api.ndarray.INDArray computeLoss(org.nd4j.linalg.api.ndarray.INDArray plNetOutputs)

Computes the NLL for PL networks according to equation (27) in [1].

Parameters:

plNetOutputs - The outputs for M_n dyads generated by a PLNet's output layer in order of their ranking (from best to worst).

Returns:

The NLL loss for the given PLNet outputs.

computeLossGradient

public static org.nd4j.linalg.api.ndarray.INDArray computeLossGradient(org.nd4j.linalg.api.ndarray.INDArray plNetOutputs,
                                                                       int k)

Computes the gradient of the NLL for PL networks w.r.t. the k-th dyad according to equation (28) in [1].

Parameters:

plNetOutputs - The outputs for M_n dyads generated by a PLNet's output layer in order of their ranking (from best to worst).

k - The ranking position with respect to which the gradient should be computed. Assumes zero-based indices, unlike the paper.

Returns:

The gradient of the NLL loss w.r.t. the k-th dyad in the ranking.