Questions tagged [multilayer-perceptrons]

For question about Multi Layer Perceptron model/architecture, its training and other related details and parameters associated with the model.

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Rank of gradient-of-loss with respect to layer weights in an MLP

The paper: https://arxiv.org/abs/2110.11309, makes the following claim at the end of page 3: The gradient of loss $L$ with respect to weights $W_l$ of an MLP is a rank-1 matrix for each of B batch ...
2 votes
1 answer
90 views

Multi-objective training involving maximization of one loss function and minimization of another

I need my model to predict $s$ from my data $x$. Additionally, I need the model to not use signals in $x$ that are predictive of a separate target $a$. My approach is to transform $x$ into a ...
1 vote
1 answer
52 views

Why is training all layers at a time effective for a multi-layer autoencoder?

This training of all layers of a CNN simultaneously is standard practice today. It is found in every CNN (AlexNet (2012), VGG, Inception, GANs, etc) and even pre-CNN networks such as Le et al. 2012. ...
4 votes
1 answer
111 views

Backpropagation equation for a variant on the usual Linear Neuron architecture

Recently I encountered a variant on the normal linear neural layer architecture: Instead of $Z = XW + B$, we now have $Z = (X-A)W + B$. So we have a 'pre-bias' $A$ that affects the activation of the ...
2 votes
2 answers
537 views

Unable to overfit using MLP

I'm building a 5-class classifier with a private dataset. Each data sample has 67 features and there are about 40000 samples. Samples of a particular class were duplicated to overcome class imbalance ...
3 votes
0 answers
40 views

Why does a neural network struggle to solve this simple problem?

Consider the following problem: Given a vector x of size dim with values between 0 and 1 (exclusive), determine if ...
0 votes
0 answers
34 views

Are autoencoders computationally cheaper than MLPs with the same number of neurons?

Are autoencoders computationally cheaper than other neural networks such as MLP with the same number of neurons? I have read in some papers that autoencoders train the network faster, and I could ...
2 votes
2 answers
107 views

Why is a simple regression problem so hard for an MLP to learn?

Consider a very simple problem, which is to find the maximum value out of a list of 5 numbers between 0 and 1. This is obviously trivial, but serves as a good example for a real-world problem I'm ...
1 vote
0 answers
58 views

Model unfit for some part of spiral data despite low error

I'm current testing a model for spiral data. After 500 epoches, loss is 0.04 but the result is still unmatch with some part of the training data. (bottom left) (source: upsieutoc.com) The model has 2 ...
0 votes
1 answer
23 views

Do Quo et al (2013) perform backpropagation between layers?

Le et al. 2013's non-weight sharing CNN has inspired me to ask two questions on this site previously. When training the three-layer autoencoder, do they compute dL/dW (where L is equation 1) ...
2 votes
1 answer
61 views

Why is automatic differentiation still used, if today's computers can calculate symbolic derivatives quite fast?

Today's computers can calculate symbolic derivatives quite fast, why is automatic differentiation still used? For example, Mathematica can handle algebraic operations with arrays. Doesn't automatic ...
3 votes
2 answers
184 views

Which online machine learning technique to use for multi-class classification problem with multiple inputs?

I have the following problem. We have $4$ separate discrete inputs, which can take any integer value between $-63$ and $63$. The output is also supposed to be a discrete value between $-63$ and $63$. ...
3 votes
3 answers
744 views

How can a neural network learn to play sudoku?

I'm just beginning to understand neural networks and I've performed a couple of successful tests with numerical series where the NN was trained to find the odd one or a missing value. It all works ...
1 vote
2 answers
52 views

What are all the possible usages of 'multilayer perceptron'?

The term 'multilayer perceptron' has been used in literature in various ways in the literature. I am presenting some of them below As a feed-forward neural network [1]. As a fully connected feed-...
2 votes
1 answer
68 views

Recent algorithms for correcting mislabeled data using multilayer perceptrons

I am doing literature research on algorithms for correcting mislabeled data using multilayer perceptrons. Found an "old" paper An algorithm for correcting mislabeled data (2001) by Xinchuan Zeng et al....
0 votes
0 answers
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What is the right way to normalize the initial weights of a fully connected layer using a SiLu (Sigmoid-weighted Linear Unit) activation function?

I've been writing a deep learning Java framework as a way for myself to learn how it all works and I have had a decent amount of success so far. Best performance is just over 90% accuracy with three ...
2 votes
1 answer
47 views

How to decode P bits that represent a random weight generator?

So I've been tasked by my neural network professor at university to replicate the following research: Intelligent Breast Cancer Diagnosis Using Hybrid GA-ANN. Each chromosome represents a possible net,...
5 votes
1 answer
253 views

How to deal with padded inputs in a fully connected feed forward network?

I have a fully connected network that takes in a variable-length input padded with 0. However, the network doesn't seem to be learning and I am guessing that the high number of zeros in the input ...
0 votes
2 answers
195 views

Concise and mathematically-oriented book on AI and neural networks suitable as a gift [closed]

I would like to buy a book about AI and neural networks written on accessible level for a 17 years old mathematically very gifted student interested in these topics. The book should contain some ...
4 votes
2 answers
972 views

Why is it called back-propagation?

While looking at the mathematics of the back-propagation algorithm for a multi-layer perceptron, I noticed that in order to find the partial derivative of the cost function with respect to a weight (...
0 votes
1 answer
247 views

How to make a proper approximation of Sine function with Neural Networks?

TL;DR; How to build a neural network that properly approximates the sine function with different ranges? Context and Question: From this question I decided to use the Sergey's answer, however I used a ...
1 vote
1 answer
65 views

Does a second-order fully-connected layer have any uses?

I was thinking about implementing second-order regression via a fully-connected layer, and I came up with this: $X$ is the input data, shaped $(features, batch\_number)$. $w0$ is the bias, shaped $(...
1 vote
1 answer
70 views

Can RNNs get inputs and produce outputs similar to the inputs and outputs of FFNNs?

RNN and LSTM models have many architectures that can be modified. We can also compose their input and output data. However, in the examples that I found on the web, the inputs and outputs of RNNs/...
3 votes
3 answers
2k views

Why must the momentum factor be in the range 0-1?

Why is it a bad idea to have a momentum factor greater than 1? What are the mathematical motivations/reasons?
1 vote
0 answers
59 views

Is the capability of RNN more than the capability of MLP?

Consider the following excerpt paragraph taken from the section titled "Recurrent Neural Networks" of the chapter 10: Sequence Modeling: Recurrent and Recursive Nets of the textbook named ...
1 vote
0 answers
44 views

Does Godel's incompleteness theorems restricts the scope of connectionist-AI?

It is well-known that Godel's incompleteness theorems restricted the reachability of symbolic-AI, which is dependent on mathematical logic. But, I am wondering whether it has any impact on the ...
1 vote
1 answer
89 views

Are the capabilities of connectionist AI and symbolic AI the same?

The universal approximation theorem says that MLP with a single hidden layer and enough number of neurons can able to approximate any bounded continuous function. You can validate it from the ...
2 votes
1 answer
318 views

Why is the backpropagation algorithm used to train the multilayer perceptron?

I've read in the book Neural Network Design, by Martin Hagan et al. (chapter 11), that, to train the feed-forward neural network (aka multilayer perceptron), one uses the backpropagation algorithm. ...
1 vote
1 answer
508 views

What is the minimum number of neurons and hidden layers needed to learn a Boolean function that maps $N$ bits to $1$ bit?

Suppose I have a Boolean function that maps $N$ bits to $1$ bit. If I understand correctly, this function will have $2^{2^N}$ possible configurations of its truth table. What is the minimum number of ...
1 vote
0 answers
61 views

Is the VC dimension of a MLP regressor a valid upper bound on how many points it can exactly fit?

I want to calculate an upper bound on how many training points an MLP regressor can fit with ~0 error. I don't care about the test error, I want to overfit as much as possible the (few) training ...
5 votes
2 answers
1k views

Can neurons in MLP and filters in CNN be compared?

I know they are not the same in working, but an input layer sends the input to $n$ neurons with a set of weights, based on these weights and the activation layer, it produces an output that can be fed ...
14 votes
3 answers
5k views

Did Minsky and Papert know that multi-layer perceptrons could solve XOR?

In their famous book entitled Perceptrons: An Introduction to Computational Geometry, Minsky and Papert show that a perceptron can't solve the XOR problem. This contributed to the first AI winter, ...
1 vote
1 answer
138 views

When should we use CNN instead of MLP?

Is CNN only applicable to time-series data or image data? When should we use CNN instead of MLP?
0 votes
1 answer
901 views

What, exactly, do mlp(64,64) and mlp(64,128,1024) mean in PointNet, and how many input neurons does 1 (x,y,z) point have?

I couldn't find out how to interpret the multilayer perceptron notation given in PointNet. Specifically, I am looking to find out what the numbers inside the parentheses of ...
1 vote
1 answer
250 views

Why doesn't the LSTM model improve the time-series forecasting significantly with respect to the MLP model?

I have recently started learning time series forecasting. I have a dataset of the weekly payment history of 10k clients over 1 year, and I want to predict the future 5 payments for a test set of 1k ...
0 votes
1 answer
80 views

About the choice of the activation functions in the Multilayer Perceptron, and on what does this depends?

I've read in this: F. Rosenblatt, Principles of neurodynamics. perceptrons and the theory of brain mechanisms that in the Multilayer Perceptron the activation functions in the second, third, ..., are ...
0 votes
0 answers
55 views

What are the math theorems regarding the Multilayer Perceptron?

I've come across a theorem "Convergence theorem Simple Perceptron" for the first time, here-> https://zaguan.unizar.es/record/69205/files/TAZ-TFG-2018-148.pdf, page 27, (is in Spanish) ...
2 votes
1 answer
141 views

Is there a mathematical theory behind why MLP can classify handwritten digits?

I'm trying to really understand how multi-layer perceptrons work. I want to prove mathematically that MLP's can classify handwritten digits. The only thing I really have is that each perceptron can ...
0 votes
0 answers
141 views

What is the difference between the forward pass of the Multi-Layer Perceptron, Deep AutoEncoder and Deep Belief Network?

Multi-Layer Perceptron (MLP), Deep AutoEncoder (DAE), and Deep Belief Network (DBN) are trained differently. However, do they follow the same process during the inference phase, i.e., do they ...
6 votes
1 answer
890 views

Why do feedforward neural networks require the inputs to be of a fixed size, while RNNs can process variable-size inputs?

Why does a vanilla feedforward neural network only accept a fixed input size, while RNNs are capable of taking a series of inputs with no predetermined limit on the size? Can anyone elaborate on this ...
1 vote
1 answer
255 views

What are examples of good free books that cover the back-propagation algorithm?

What are examples of good free books that cover the back-propagation used to train multilayer perceptrons? I've just started to learn about artificial neural networks, so I'm looking for books that ...
5 votes
2 answers
279 views

Is a multilayer perceptron a recursive function?

I read somewhere that a multilayer perceptron is a recursive function in its forward propagation phase. I am not sure, what is the recursive part? For me, I would see an MLP as a chained function. So, ...
3 votes
1 answer
473 views

Why does every neuron in hidden layers of a multi-layer perceptron typically have the same activation function? [duplicate]

Why does every neuron in a hidden layer of a multi-layer perceptron (MLP) typically have the same activation function as every other neuron in the same or other hidden layers (so I exclude the output ...
6 votes
4 answers
1k views

What are some datasets to train an MLP on simple tasks? [closed]

I have implemented an MLP. Now, I want to train it to solve simple tasks. Are there any data sets to train the MLP on simple tasks, that is, tasks with a small number of inputs and outputs? I ...
0 votes
0 answers
56 views

How to draw a 3-dimensonal shape's neural network

I am reading an exam question about NN (that I cannot publish, for copyright reasons). The question says: 'Construct a rectangle in 2D space. Define the lines, and then define the weights and ...
15 votes
0 answers
480 views

What is the number of neurons required to approximate a polynomial of degree n?

I learned about the universal approximation theorem from this guide. It states that a network even with a single hidden layer can approximate any function within some bound, given a sufficient number ...
2 votes
2 answers
551 views

Why don't neural networks project the data into higher dimensions first, then reduce the size of each layer thereafter?

Background From my understanding (and following along with this blog post), (deep) neural networks apply transformations to the data such that the data's representation to the next layer (or ...
0 votes
1 answer
592 views

Keras DQN Model with Multiple Inputs and Multiple Outputs [closed]

I am trying to create a DQN agent where I have 2 inputs: the agent's position and a matrix of 0s and 1s. The output is composed of the agent's new chosen position, a matrix of 0s and 1s (different ...
1 vote
2 answers
723 views

How is the error calculated with multiple output neurons in the neural network?

Machine Learning books generally explains that the error calculated for a given sample $i$ is: $e_i = y_i - \hat{y_i}$ Where $\hat{y}$ is the target output and $y$ is the actual output given by the ...
3 votes
1 answer
74 views

Is there a common way to build a neural network that seeks to extract spatial and temporal information simultaneously?

Is there a common way to build a neural network that seeks to extract spatial and temporal information simultaneously? Is there an agreed up protocol on how to extract this information? What ...