using System;

using System.Collections.Generic;

using System.Text;

using Tensorflow.Operations.Activation;

using static Tensorflow.Binding;

namespace Tensorflow.Keras

{

public class Activations: IActivationsApi

{

private static Dictionary<string, Activation> _nameActivationMap;

private static Activation _linear = new Activation()

{

Name = "linear",

ActivationFunction = (features, name) => features

};

private static Activation _relu = new Activation()

{

Name = "relu",

ActivationFunction = (features, name) => tf.Context.ExecuteOp("Relu", name, new ExecuteOpArgs(features))

};

private static Activation _relu6 = new Activation()

{

Name = "relu6",

ActivationFunction = (features, name) => tf.Context.ExecuteOp("Relu6", name, new ExecuteOpArgs(features))

};

private static Activation _sigmoid = new Activation()

{

Name = "sigmoid",

ActivationFunction = (features, name) => tf.Context.ExecuteOp("Sigmoid", name, new ExecuteOpArgs(features))

};

private static Activation _softmax = new Activation()

{

Name = "softmax",

ActivationFunction = (features, name) => tf.Context.ExecuteOp("Softmax", name, new ExecuteOpArgs(features))

};

private static Activation _tanh = new Activation()

{

Name = "tanh",

ActivationFunction = (features, name) => tf.Context.ExecuteOp("Tanh", name, new ExecuteOpArgs(features))

};

private static Activation _mish = new Activation()

{

Name = "mish",

ActivationFunction = (features, name) => features * tf.math.tanh(tf.math.softplus(features))

};

/// <summary>

/// Register the name-activation mapping in this static class.

/// </summary>

/// <param name="activation"></param>

private static void RegisterActivation(Activation activation)

{

_nameActivationMap[activation.Name] = activation;

}

static Activations()

{

_nameActivationMap = new Dictionary<string, Activation>();

RegisterActivation(_relu);

RegisterActivation(_relu6);

RegisterActivation(_linear);

RegisterActivation(_sigmoid);

RegisterActivation(_softmax);

RegisterActivation(_tanh);

RegisterActivation(_mish);

}

public Activation Linear => _linear;

public Activation Relu => _relu;

public Activation Relu6 => _relu6;

public Activation Sigmoid => _sigmoid;

public Activation Softmax => _softmax;

public Activation Tanh => _tanh;

public Activation Mish => _mish;

public Activation GetActivationFromName(string name)

{

if (name == null)

{

return _linear;

}

if (!_nameActivationMap.TryGetValue(name, out var res))

{

throw new Exception($"Activation {name} not found");

}

else

{

return res;

}

}

}

}