Questions tagged [machine-learning]

Implementation questions about machine learning algorithms. General questions about machine learning (concepts, theory, methodology, terminology, etc.) should be posted to their specific communities.

Machine learning revolves around developing self-learning computer algorithms that function by virtue of discovering patterns in data and making intelligent decisions based on such patterns.

Machine learning is a subfield of computer science that evolved from the study of pattern recognition and computational learning theory in artificial intelligence. Machine learning explores the construction and study of algorithms that can learn from and make predictions about data. Such algorithms operate by building a model from example inputs in order to make data-driven predictions or decisions rather than following strictly static program instructions.

NOTE: If you want to use this tag for a question not directly concerning implementation, then consider posting on Cross Validated, Data Science, or Artificial Intelligence instead; otherwise you're probably off-topic. Please choose one site only and do not cross-post to more than one - see Is cross-posting a question on multiple Stack Exchange sites permitted if the question is on-topic for each site? (tl;dr: no).

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What is the role of the bias in neural networks?

I'm aware of the gradient descent and the back-propagation algorithm. What I don't get is: when is using a bias important and how do you use it? For example, when mapping the AND function, when I use two inputs and one output, it does not give the…
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What is the difference between a generative and a discriminative algorithm?

What is the difference between a generative and a discriminative algorithm?
unj2
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A simple explanation of Naive Bayes Classification

I am finding it hard to understand the process of Naive Bayes, and I was wondering if someone could explain it with a simple step by step process in English. I understand it takes comparisons by times occurred as a probability, but I have no idea…
Aeonitis
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Epoch vs Iteration when training neural networks

What is the difference between epoch and iteration when training a multi-layer perceptron?
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What are logits? What is the difference between softmax and softmax_cross_entropy_with_logits?

In the tensorflow API docs they use a keyword called logits. What is it? A lot of methods are written like: tf.nn.softmax(logits, name=None) If logits is just a generic Tensor input, why is it named logits? Secondly, what is the difference between…
Shubhashis
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How does the Google "Did you mean?" Algorithm work?

I've been developing an internal website for a portfolio management tool. There is a lot of text data, company names etc. I've been really impressed with some search engines ability to very quickly respond to queries with "Did you mean: xxxx". I…
Andrew Harry
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What is the meaning of the word logits in TensorFlow?

In the following TensorFlow function, we must feed the activation of artificial neurons in the final layer. That I understand. But I don't understand why it is called logits? Isn't that a mathematical function? loss_function =…
395
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What are advantages of Artificial Neural Networks over Support Vector Machines?

ANN (Artificial Neural Networks) and SVM (Support Vector Machines) are two popular strategies for supervised machine learning and classification. It's not often clear which method is better for a particular project, and I'm certain the answer is…
Channel72
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Convert array of indices to one-hot encoded array in NumPy

Given a 1D array of indices: a = array([1, 0, 3]) I want to one-hot encode this as a 2D array: b = array([[0,1,0,0], [1,0,0,0], [0,0,0,1]])
James Atwood
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How to implement the Softmax function in Python

From the Udacity's deep learning class, the softmax of y_i is simply the exponential divided by the sum of exponential of the whole Y vector: Where S(y_i) is the softmax function of y_i and e is the exponential and j is the no. of columns in the…
alvas
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What is the difference between supervised learning and unsupervised learning?

In terms of artificial intelligence and machine learning, what is the difference between supervised and unsupervised learning? Can you provide a basic, easy explanation with an example?
279
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What is the difference between linear regression and logistic regression?

When we have to predict the value of a categorical (or discrete) outcome we use logistic regression. I believe we use linear regression to also predict the value of an outcome given the input values. Then, what is the difference between the two…
London guy
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How to interpret loss and accuracy for a machine learning model

When I trained my neural network with Theano or Tensorflow, they will report a variable called "loss" per epoch. How should I interpret this variable? Higher loss is better or worse, or what does it mean for the final performance (accuracy) of my…
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Is there a rule-of-thumb for how to divide a dataset into training and validation sets?

Is there a rule-of-thumb for how to best divide data into training and validation sets? Is an even 50/50 split advisable? Or are there clear advantages of having more training data relative to validation data (or vice versa)? Or is this choice…
robguinness
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How do I initialize weights in PyTorch?

How do I initialize weights and biases of a network (via e.g. He or Xavier initialization)?
Fábio Perez
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