How to normalize Keras network output in a regression problem that demands output with unit L2 norm?












0















My regression problem requires that the network output y has unit norm ||y|| = 1.. I would like to impose that as a Lambda layer after the linear activation:



from keras import backend as K  
...
model.add(Dense(numOutputs, activation='linear'))
model.add(Lambda(lambda x: K.l2_normalize(x)))


The backend is TensorFlow. The code compiles but the network predicts output vectors with distinct norms (the norm is not 1 and varies).



Any hints regarding what I am doing wrongly?










share|improve this question





























    0















    My regression problem requires that the network output y has unit norm ||y|| = 1.. I would like to impose that as a Lambda layer after the linear activation:



    from keras import backend as K  
    ...
    model.add(Dense(numOutputs, activation='linear'))
    model.add(Lambda(lambda x: K.l2_normalize(x)))


    The backend is TensorFlow. The code compiles but the network predicts output vectors with distinct norms (the norm is not 1 and varies).



    Any hints regarding what I am doing wrongly?










    share|improve this question



























      0












      0








      0








      My regression problem requires that the network output y has unit norm ||y|| = 1.. I would like to impose that as a Lambda layer after the linear activation:



      from keras import backend as K  
      ...
      model.add(Dense(numOutputs, activation='linear'))
      model.add(Lambda(lambda x: K.l2_normalize(x)))


      The backend is TensorFlow. The code compiles but the network predicts output vectors with distinct norms (the norm is not 1 and varies).



      Any hints regarding what I am doing wrongly?










      share|improve this question
















      My regression problem requires that the network output y has unit norm ||y|| = 1.. I would like to impose that as a Lambda layer after the linear activation:



      from keras import backend as K  
      ...
      model.add(Dense(numOutputs, activation='linear'))
      model.add(Lambda(lambda x: K.l2_normalize(x)))


      The backend is TensorFlow. The code compiles but the network predicts output vectors with distinct norms (the norm is not 1 and varies).



      Any hints regarding what I am doing wrongly?







      python tensorflow machine-learning keras regression






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 23 '18 at 13:33









      today

      11.3k22239




      11.3k22239










      asked Nov 23 '18 at 6:01









      EdsonEdson

      84




      84
























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          0














          The problem is that you haven't passed the axis argument to the K.l2_normalize function. As a result it would normalize all the elements in the whole batch so that their norm would be equal to one. To resolve this, just pass axis=-1 to normalize over the last axis:



          model.add(Lambda(lambda x: K.l2_normalize(x, axis=-1)))  





          share|improve this answer
























          • Great. This solves the issue. I get norm = 1 now.

            – Edson
            Nov 23 '18 at 16:14











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          1 Answer
          1






          active

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          active

          oldest

          votes









          0














          The problem is that you haven't passed the axis argument to the K.l2_normalize function. As a result it would normalize all the elements in the whole batch so that their norm would be equal to one. To resolve this, just pass axis=-1 to normalize over the last axis:



          model.add(Lambda(lambda x: K.l2_normalize(x, axis=-1)))  





          share|improve this answer
























          • Great. This solves the issue. I get norm = 1 now.

            – Edson
            Nov 23 '18 at 16:14
















          0














          The problem is that you haven't passed the axis argument to the K.l2_normalize function. As a result it would normalize all the elements in the whole batch so that their norm would be equal to one. To resolve this, just pass axis=-1 to normalize over the last axis:



          model.add(Lambda(lambda x: K.l2_normalize(x, axis=-1)))  





          share|improve this answer
























          • Great. This solves the issue. I get norm = 1 now.

            – Edson
            Nov 23 '18 at 16:14














          0












          0








          0







          The problem is that you haven't passed the axis argument to the K.l2_normalize function. As a result it would normalize all the elements in the whole batch so that their norm would be equal to one. To resolve this, just pass axis=-1 to normalize over the last axis:



          model.add(Lambda(lambda x: K.l2_normalize(x, axis=-1)))  





          share|improve this answer













          The problem is that you haven't passed the axis argument to the K.l2_normalize function. As a result it would normalize all the elements in the whole batch so that their norm would be equal to one. To resolve this, just pass axis=-1 to normalize over the last axis:



          model.add(Lambda(lambda x: K.l2_normalize(x, axis=-1)))  






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 23 '18 at 13:31









          todaytoday

          11.3k22239




          11.3k22239













          • Great. This solves the issue. I get norm = 1 now.

            – Edson
            Nov 23 '18 at 16:14



















          • Great. This solves the issue. I get norm = 1 now.

            – Edson
            Nov 23 '18 at 16:14

















          Great. This solves the issue. I get norm = 1 now.

          – Edson
          Nov 23 '18 at 16:14





          Great. This solves the issue. I get norm = 1 now.

          – Edson
          Nov 23 '18 at 16:14




















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