Package smile.deep.activation

Class Sigmoid

java.lang.Object
smile.deep.activation.Sigmoid
All Implemented Interfaces:
Serializable, ActivationFunction
public class Sigmoid extends Object implements ActivationFunction
Logistic sigmoid function: sigmoid(v)=1/(1+exp(-v)). For multi-class classification, each unit in output layer corresponds to a class. For binary classification and cross entropy error function, there is only one output unit whose value can be regarded as posteriori probability.
See Also:

  • Constructor Details

    • Sigmoid

      public Sigmoid()
      Constructor.

  • Method Details

    • name

      public String name()
      Description copied from interface: ActivationFunction
      Returns the name of activation function.
      Specified by:
      name in interface ActivationFunction
      Returns:
      the name of activation function.

    • f

      public void f(double[] x)
      Description copied from interface: ActivationFunction
      The output function.
      Specified by:
      f in interface ActivationFunction
      Parameters:
      x - the input vector.

    • g

      public void g(double[] g, double[] y)
      Description copied from interface: ActivationFunction
      The gradient function.
      Specified by:
      g in interface ActivationFunction
      Parameters:
      g - the gradient vector. On input, it holds W'*g, where W and g are the weight matrix and gradient of upper layer, respectively. On output, it is the gradient of this layer.
      y - the output vector.