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1500 questions
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2 answers

XGBoost and Random Forest: ntrees vs. number of boosting rounds vs. n_estimators

So I understand the main difference between Random Forests and GB Methods. Random Forests grow parallel trees and GB Methods grow one tree for each iteration. However, I am confused on the vocab used with scikit's RF regressor and xgboost's…
Jack Armstrong
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How to prevent vanishing gradient or exploding gradient?

Whats causing the vanishing gradient or exploding gradient to occur, and what are the measures to be taken to prevent it?
yashdk
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Optimising for Brier objective function directly gives worse Brier score than optimising with custom objective - what does it tell me?

I am training an XGBoost model and as I care the most about resulting probabilities, not classification itself I have chosen Brier score as a metric for my model, so that probabilities would be well calibrated. I tuned my hyperparameters using…
Xaume
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2 answers

How to normalize data without knowing the min and max values?

I have a Lending club dataset from Kaggle; it contains many different columns: there are for example dummy variables, years, amount of the loan...ect I want to normalize the data in the training and test set but I have to use the Min and Max of the…
Ghassen Ben Hamida
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1 answer

Train a GAN on "before and after" images of dental surgeries

I want a GAN to train on "before and after" images of dental surgeries; so that it can generate "after" pictures for fresh patients. Input images are like these:…
Lakshay Dulani
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9
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1 answer

How fbprophet cross validation works

I am facing some issues to understand how cross_validation function works in fbprophet packages. I have a time series of 68 days (only business days) grouped by 15min and a certain metric : 00:00 5 00:15 2 00:30 10 etc 23:45 26 And I really…
Katy
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1 answer

Understanding dropout and gradient descent

I am looking at how to implement dropout on deep neural networks and found something counter intuitive. In the forward phase dropout mask activations with a random tensor of 1s and 0s to force net to learn the average of the weights. This help the…
emanuele
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9
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5 answers

Any idea about application of deep dream?

Recently Google publicized interesting deep dream. Besides art generation such as http://deepdreamgenerator.com/, do you see any potential applications of deep dream in computer vision or machine learning?
rudky martin
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1 answer

sklearn - overfitting problem

I'm looking for recommendations as to the best way forward for my current machine learning problem The outline of the problem and what I've done is as follows: I have 900+ trials of EEG data, where each trial is 1 second long. The ground truth is…
Simon
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Can I use LSTM models to evaluate multiple, independent time series?

Let's say that I would like to predict the temperature tomorrow. I could use the approach whereby I train a model based on a time-series dataset collected from a single location (for example, see this excellent…
CharismaticChromoFauna
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5 answers

How can we extract fields from images?

I am making an document parser which extracts data fields from the documents and store them in a structured way. Each field in my dataset is horizontal which is easy to extract. But the model fails on following type of example - Is there any way…
hR 312
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Why continuous features are more important than categorical features in decision tree models?

I have both categorical and continuous features in my prediction model and want to select (and rank) most important features. I have converted all categorical variables into dummy variables using one hot encoding (for better interpretation in my…
Shahab Kazemi
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1 answer

Using a GAN discriminator as a standalone classifier

The goal of the discriminator in a GAN is to distinguish between real inputs and inputs synthesized by the generator. Suppose I train a GAN until the generator is good enough to fool the discriminator much of the time. Could I then use the…
rgov
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1 answer

Feature selection for Support Vector Machines

My question is three-fold In the context of "Kernelized" support vector machines Is variable/feature selection desirable - especially since we regularize the parameter C to prevent overfitting and the main motive behind introducing kernels to a SVM…
Nitin Srivastava
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3 answers

Is (nearly) all data separable?

Suppose I have some data set with two classes. I could draw a decision boundary around each data point belonging to one of these classes, and hence, separate the data, like so: Where the red lines are the decision boundaries around the data points…
Data
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