Request help on the cost function

[glhfgg1024]

Hi dear authors, thanks a lot for your sharing code! I have a question, in the design of RiskLayer, the following line:
https://github.com/CancerDataScience/SurvivalNet/blob/83b99fffea15bca5f0017fa08bef61de9f165eea/survivalnet/model/RiskLayer.py#L46

Do we need to add a negative sign? Because the negative log partial likelihood (Eqn. 1 in your paper) has this sign. Thanks.