Questions tagged [activation-function]

Activation function is a non-linear transformation, usually applied in neural networks to the output of the linear or convolutional layer. Common activation functions: sigmoid, tanh, ReLU, etc.

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How to create custom Activation functions in Keras / TensorFlow?

I'm using keras and I wanted to add my own activation function myf to tensorflow backend. how to define the new function and make it operational. so instead of the line of code: ...
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785 views

Why there is no exact picture of softmax activation function?

I was wondering why there is no precise picture of the softmax activation function on the internet. Is it difficult for the plot or what is the reason behind that since I want to compare it with a ...
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What are the best activation functions for Binary text classification in neural networks?

I know that there are many activation functions like Relu, sigmoid, tanh ..etc, I just want to know the best one for my case - Binary text classification. I have heard that Relu is best for Binary ...
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What are contexts where a perceptron model could be defined?

per this post, a perceptron could use the logit function as the activation function. per wiki In the context of neural networks, a perceptron is an artificial neuron using the Heaviside step ...
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Derivative of activation function used in gradient descent algorithms

Why is it necessary to calculate the derivative of activation functions while updating model( regression or NN) parameters? Why is the constant gradient of linear functions considered as a ...
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1answer
24 views

Deep Neural Network and Activation Function

I want to know why we need Activation function in DNN hidden layers. I know a bit, like it will help us in, Increasing model complexity and introduce non-linearity Avoiding Gradient Vanishing ...
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276 views

How does cost function change by choice of activation function (ReLU, Sigmoid, Softmax)?

I am new to ML and as I take courses for the area DL, I am wondering, by our choice of activation function for the last layer, whether we take sigmoid, relu or softmax, would the formula for ...
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1answer
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Using LeakyRelu as activation function in CNN and best alpha for it

Since if we do not declare the activation function, the default will be set as linear for Conv2D layer. Is it true to write: <...
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1answer
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Confusion regarding the Working mechanism of Activation function

For binary classification irrespective of the model used, the sigmoid function is a good choice for output layer because the actual output value ‘Y’ is either 0 or 1 so it makes sense for predicted ...
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358 views

Why do we use a softmax activation function in Convolutional Autoencoders?

I have been working on an image segmentation project where I have created a convolutional autoencoder. I saw this image and implemented it using Keras. At the output layer, the author has used the ...
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Exponential Linear Units (ELU) vs $log(1+e^x)$ as the activation functions of deep learning

It seems ELU (Exponential Linear Units) is used as an activation function for deep learning. But its' graph is very similar to the graph of $log(1+e^x)$. So why has $log(1+e^x)$ not been used as the ...
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How to adjust the Regression with ANN for last part of function

The Blue dots represent the required function and the Black ones represent the predicted function I am using keras with the following code:- ...
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Can the vanishing gradient problem be solved by multiplying the input of tanh with a coefficient?

To my understanding, the vanishing gradient problem occurs when training neural networks when the gradient of each activation function is less than 1 such that when corrections are back-propagated ...
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1answer
66 views

Quasi-linearity in deep learning regression problems (sports betting)

I’m attempting to build a sports betting model that aims to predict final scores for games. I’ve had some promising early results for US college football just by using linear regression to form team ...
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Gradient Descent in ReLU Neural Network

I’m new to machine learning and recently facing a problem on back propagation of training a neural network using ReLU activation function shown in the figure. My problem is to update the weights ...
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What is GELU activation?

I was going through BERT paper which uses GELU (Gaussian Error Linear Unit) which states equation as $$ GELU(x) = xP(X ≤ x) = xΦ(x).$$ which in turn is approximated to $$0.5x(1 + tanh[\sqrt{ 2/π}(x + ...
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What are best activation and regularization method for LSTM?

In Keras there are: ...
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What activation function should I use for a specific regression problem?

Which is better for regression problems create a neural net with tanh/sigmoid and exp(like) activations or ReLU and linear? Standard is to use ReLU but it's brute force solution that requires certain ...
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1answer
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Can we use ReLU activation function as the output layer's non-linearity?

I have trained a model with linear activation function for the last dense layer, but I have a constraint that forbids negative values for the target which is a continuous positive value. Can I use ...
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1answer
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Are there any activation functions which on inputting integer data will produce the output as integers?

Idea is to create the model for ethereum mining which deals with only integer data.
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141 views

activation functions in multiple layers in CNNs

An activation function (say sigmoid) is necessary on the final fully connected layer. But why is an activation function applied on the convolution layer too? As I understand it, the activation ...
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Product of dot products in neural network

In a neural network, it is common to compute a dot product of the form $$\langle w, x \rangle = w_1 x_1 + w_2 x_2 + \ldots + w_n x_n$$ and use it as argument to some activation function. This is ...
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What's the correct reasoning behind solving the vanishing/exploding gradient problem in deep neural networks.?

I have read several blog posts where the solution to solve the vanishing/exploding gradient problem in a deep neural network is suggested to be using Relu activation function instead of tanH & ...
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Regression with -1,1 target range - Should we use a tanh activation in the last 1 unit dense layer?

Say in a regression problem the target range to be between [0,1] or [-1,1], and say the last layer of the network is as ...
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Obtaining correctly gradient in neural network of output with respect to input. Is relu a bad option as the activation function?

My neural network is made only by two hidden fully connected units. I've obtained very good results using relu as the activation function, and only good results using softplus. My main purpose is to ...
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1answer
898 views

What does it mean for an activation function to be “saturated/non-saturated”?

For context, in this paper Several RNN variants such as the long short-term memory (LSTM) [10, 18] and the gated recurrent unit (GRU) [5] have been proposed to address the gradient problems. ...
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663 views

Why activation function is not needed during the runtime of an Word2Vec model

In Word2Vec trainable model, there are two different weight matrix. The matrix $W$ from input-to-hidden layer and the matrix $W'$ from hidden-to-output layer. Referring to this article, I understand ...
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1answer
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Implementing a custom hard sigmoid function

I need to implement an activation function that is similar to Keras's "hard-sigmoid", only for different limit values: 0 if x < 0 1 if x > 1 x if 0 <= x <= 1 How do I implement it with a ...
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1answer
340 views

The mix of leaky Relu at the first layers of CNN along with conventional Relu for object detection

First of all, I know the usage of leaky RELUs and some other relevant leaky activation functions as well. However I have seen in a lot of papers on object detection tasks (e.g YOLO) to use this type ...
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4answers
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How does Sigmoid activation work in multi-class classification problems

I know that for a problem with multiple classes we usually use softmax, but can we also use sigmoid? I have tried to implement digit classification with sigmoid at the output layer, it works. What I ...
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1answer
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“Each agent was evaluated every 250,000 training frames for 135,000 validation frames” What does this sentences stands for? in DQN nature paper?

In nature paper of DQN by DeepMind, DQN is compared to linear function but they does not said what is this linear function? They compared with some linear functions? 0- What is the meaning of this ...
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How to use LeakyRelu as activation function in sequence DNN in keras?When it perfoms better than Relu?

How do you use LeakyRelu as an activation function in sequence DNN in keras? If I want to write something similar to: ...
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1answer
287 views

best activation function for ensemble?

i have created some logistic regression model (different preprocessing) with softmax function. and i mix all model with an ensemble with a hierarchical method. so the output of all model (base) will ...
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1answer
29 views

Restricting the output of a model didn't improve the loss value of the model evaluation

There is a deep model for prediction. The outputs are some numbers between 0 and 80. (In the dataset the outputs are 0-80) The model Loss value is 70 and I would like to reduce it. I printed the ...
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2k views

Neural network example not working with sigmoid activation function

I'm running the Neural Network example written in in BogoToBogo The program worked fine: ...
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1answer
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Why is the softmax function often used as activation function of output layer in classification neural networks?

What special characteristics of the softmax function makes it a favourite choice as activation function in output layer of classification neural networks?
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1answer
342 views

How can ReLU ever fit the curve of x²?

As far as I understand (pardon me if I am wrong) the activation functions in a neural network go through the following transformations: Multiplication by constants(weights) to x ( $f(ax)$ , $f(x)$ ...
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1answer
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How to display the value of activation?

I have built my network and would like to see how the activation of a particular layer change after each epoch of training. For example, as code shown below, I want to see the activation values of "...
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4answers
69 views

Few activation functions handling various problems - neural networks

How can a few activation functions in neural networks handle so many different problems? I know some basics theory behind ANN, but I can't get what functions like the sigmoid function etc. have in ...
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959 views

Understanding of threshold value in a neural network

Consider the hypothetical neural network here $o_1$ is the output of neuron 1. $o_2$ is the output of neuron 2. $w_1$ is the weight of connection between 1 and 3. $w_2$ is the weight of connection ...
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Activation function vs Squashing function

This may seem like a very simple and obvious question, but I haven't actually been able to find a direct answer. Today in a video explaining deep neural networks I came across the term Squashing ...
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1answer
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Properly using activation functions of neural network

I'm trying to understand the hidden layers of neural networks. Input layer section covers the steps that I use before passing information to hidden layer where concerns appear. Input Layer: From my ...
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2answers
1k views

Alternatives to linear activation function in regression tasks to limit the output

I want to know whether there is a way to limit the output of a regression deep model. Suppose that I want my model outputs values which are in a specified range and penalizes the outputs which are not ...
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0answers
82 views

Cross error loss function cause division by zero error

How to calculate cross entropy when actual output is 0? Would not it give indf brcause of log(0) and the cross entropy for binary classification is given by: -(ylog(actual_output)+(1-y)*(1-...
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Is it possible to customize the activation function in scikit-learn's MLPRegressor?

Similar to this question about MLPClassifier, I suspect the answer is 'no' but I will ask it anyway. Is it possible to change the activation function of the output layer in an MLPRegressor neural ...
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Weights in neural network

So I am newbie in deep learning, I came across activation functions which gives an output and compares it to label, if it's wrong, it adjusts its weight until it gives the same output as labelled data ...
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2answers
101 views

Homemade deep learning library: numerical issue with relu activation

For the sake of learning the finer details of a deep learning neural network, I have coded my own library with everything (optimizer, layers, activations, cost function) homemade. It seems to work ...
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1answer
269 views

What exactly is the “hyperbolic” tanh function used in the context of activation functions?

I know the plot of $\tanh$ activation function looks like. I also know that its output has a range of $[-1, 1]$. Furthermore, I also know the it is defined as follows $$ \tanh(x) = \frac{\sinh(x)}{...
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How to Implement Biological Neuron Activations in Artificial Neural Networks

In artificial neural networks, activation functions are used for neurons, i.e. the sigmoid activation: Which can be implemented in code as (in Python): ...
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Is classifier able to say there's no-such-case?

I am a starter in ML and I need some help... The problem Assume that I have a classifier which can classify left hand / right hand well. I am curious whether it can decide whether there's a hand in ...