Questions tagged [ensemble]

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3answers
459 views

"ValueError: Data cardinality is ambiguous" in model ensemble with 2 different inputs

I am trying a simple model ensemble with 2 different input datasets and 1 output. I want to get predictions for one dataset and hope model will extract some useful features from the second one. I get ...
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0answers
8 views

Is XGBoost active in the Gradient Boosting widget on the Orange platform?

When I open the Gradient Boosting widget xgboost is grayed out even though it is described in detail under the documentation section on Orange. The two options are Gradient Boosting (scikit-learn) and ...
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0answers
17 views

Tuning hyper parameters for different models with caretList

I'm trying to train an ensemble using the caretList function in the caret package. I'm using these models: ...
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1answer
30 views

How to assign a weight for classifiers when using weighted majority voting?

I am trying to apply weighted majority voting on an ensemble as a combiner method. I read different papers and articles, however, I am still a bit lost on: How the weighted majority voting works How ...
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1answer
27 views

What are some good models to complement XGBOOST in stacking?

What are some good models to complement XGBOOST via stacking in typical Kaggle datascience competition? I realize XGBoost with well-tuned hyperparamters are generally quite good already.
2
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1answer
46 views

How do I combine predictions from classifiers for two different problem?

I am working on a classification problem for predicting whether the shipment is going to be late or not. I would say the classifier is mediocre at predicting the positive class at the moment. But the ...
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0answers
18 views

How to write decider function for multiple models

I have trained two classifiers .. Text Classification and Image Classification. So both models gives score for each class. For example there are 3 classes. Each model give array of 3 confidence score ...
0
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1answer
23 views

Individual models gives quite same distribution on Test set, whereas Ensembling gives better result but very different distribution

I am working on a binary classification problem with unbalanced data (17% for positive class). The problem is as following: My three individual models when predicting on the test set (for which I don'...
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0answers
24 views

Any insights on gradient boosting algorithms for classification task with large class number?

Recently I have been learning Gradient Boosting (GB) on multi-class classification. I searched Google Scholar for a while and found one paper on multi-class classification using GB 1. However, little ...
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0answers
40 views

How does stacking help Bias and Variance?

How does stacking help in terms of bias and variance? I have a hunch that stacking can help reduce bias but i am not sure, could someone refer to a paper?
1
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3answers
123 views

Ensembling expressions

I have two models, $m_1$ and $m_2$, and I want to ensemble them into a final model. I want to be able weight one or the other more according to a grid search. There are two main ideas that come to my ...
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1answer
221 views

How to train with cross validation? and which f1 score to choose?

I got similar results in 2 models which consists of similar algorithms. Model 1 with cv=10 has a f1'micro' of 0.941. See code below. Model 2 only train test split (no cv) has f1'micro' 0.953. Now here ...
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0answers
66 views

What is the best way to use Early Stopping in an ensemble (stacking) model?

I have a training and a test dataset. I would like to use the output of Model A in an ensemble model. However, I would like to use early stopping. Usually, I would create Model A for each K-fold (on ...
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2answers
30 views

Can i use other regression types that arent based in decision trees to use it like a weak learners in gradient boosting?

I was thinking if i can use polynomial regression like a weak learners in gradient boosting but i read that decision trees are used for that and i cannot find anything that show me the possibility of ...
3
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1answer
133 views

Bagging vs pasting in ensemble learning

This is a citation from "Hands-on machine learning with Scikit-Learn, Keras and TensorFlow" by Aurelien Geron: "Bootstrapping introduces a bit more diversity in the subsets that each predictor is ...
1
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0answers
11 views

Domain specific language to describe ensemble model

I'm looking for some tool/library/widely used approach to describe Hierarchical Model structure like ensemble: It's absolutely straightforward how to do it with simple ensemble like It can be ...
4
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1answer
75 views

Visualizing F-score differences in information extraction

I have several corpora and NLP systems (including a few merge ensembles of output of these systems combined in unions and intersections) with which I have extracted the annotation span sets {(begin, ...
3
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1answer
72 views

Physical modelling with neural networks - single output + stack ensemble vs multi-output

We are trying to replace an existing physical model (8 inputs/7 outputs) with artificial neural networks. The physics behind the existing model is mainly thermodynamics of humid air for air ...
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1answer
230 views

Handling Categorical Features on NGBoost

Recently I have been doing some research on NGBoost, but I could not see any parameter for categorical features. Is there any parameter that I missed? ...
1
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1answer
24 views

What should I use as training data for base (level 1) classifiers in ensembling?

Can I just take all training data that I have, train the base models on them and then take their results and use them for training level 2 model? Is this a good practice, or should it be done ...
2
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1answer
481 views

What is the difference between horizontal and vertical ensemble?

I am looking at different ways to do model ensembling and I came across the terms horizontal and vertical blending/ensembling but it is not well defined. My questions will be: What is the ...
3
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1answer
559 views

grid search - optimal weighting of classifiers

I am using three different of the shelf classifiers. It's a three class classification task. I want to calculate the optimal weights (c1weight, c2weight, c3weight) for each classifier (real task more ...
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1answer
26 views

How can the Adaboost technique be called an ensemble learning technique?

I have read that in ensemble learning we use the outputs of various classifiers to make the predictive modeling better but in Adaboost we just use one classifier and we make it a strong learner but ...
1
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1answer
45 views

How can I make ROC and compute AUC?

I created a boosting tree and got the probability for each tuple in my testing set. But I'm confused on how to combine each probability. Can someone tell me how to combine the probabilities?
2
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2answers
634 views

Combining Classifiers with different Precision and Recall values

Suppose I have two binary classifiers, A and B. Both are trained on the same set of data, and produce predictions on a different (but same for both classifiers) set of data. The precision for A is ...
2
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1answer
121 views

When and how to use bagging?

Can all types of ML methods benefit from bagging? Decision Tree Classification seems always be the go-to example of bagging, what about other classifiers or regressions? When it's suitable to do ...
1
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2answers
545 views

How to visualize Ensemble Models ( Random Forest) with 1000 estimators

I am working on classification problem where I need to categorize the user in buy/ non-buy category. I have around 100 + features or predictors to predict the behavior of user. I tried to implement ...
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0answers
438 views

How to create an ensemble in tensorflow using tf.estimator?

I have created a neural network using tensorflow's estimator API: ...
2
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2answers
389 views

xgboost cannot identify perfectly fitting regression line

For a dataset I want to use xgboost for the optimal ensembling of $n$ forecasts instead of just using their arithmetic mean for combination. I found that xgboost generates forecasts that are worse ...
6
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1answer
111 views

Gridsearch XGBoost for ensemble. Do I include first-level prediction matrix of base learners in train set?

I'm not quite sure how I should go about tuning xgboost before I use it as a meta-learner in ensemble learning. Should I include the prediction matrix (ie. df containing columns of prediction results ...
4
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1answer
971 views

Geometric and harmonic means in ensembling methods

When using ensembling methods for regression, a common approach is to average (using the arithmetic mean) the outputs of the weak learners in order to obtain the output of the ensemble. Is there a ...
5
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1answer
177 views

Methods for ensembling ranked lists?

I was wondering if there's a good way to use ensembling when I have two or more algoritims producing ranked lists. That is, suppose I have the following datasets consisting of ordered lists (higher ...
5
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3answers
274 views

How to create an ensemble that gives precedence to a specific classifier

Suppose that in a binary classification task, I have separate classifiers A, B, and C. If I ...
1
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1answer
83 views

Can clustering my data first help me learn better classifiers?

I was thinking about this lately. Let's say that we have a very complex space, which makes it hard to learn a classifier that can efficiently split it. But what if this very complex space is actually ...