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Question: <p>I've noticed that UMAP is often used in combination with other clustering algorithms, such as K-means, DBSCAN, HDBSCAN. However, from what I've understood, UMAP can be used for clustering tasks. So why I've noticed people using it primarily as a dimensionality reduction technique?</p>
<p>Here an example of... | https://datascience.stackexchange.com/questions/120574/why-is-umap-used-in-combination-with-other-clustering-algorithm |
Question: <p>I have a dataset with vectors in 2-dimensional space that form separate sequences (paths). Full data is presented below: <a href="https://i.sstatic.net/NRYF5.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/NRYF5.png" alt="enter image description here"></a>,
while a random sample of 5 paths l... | https://datascience.stackexchange.com/questions/42166/what-clustering-algorithm-is-appropriate-for-clustering-paths |
Question: <p>Is the following statement true? <a href="https://stats.stackexchange.com/q/256778">https://stats.stackexchange.com/q/256778</a></p>
<blockquote>
<p>The value of cosine similarity between two terms itself is not indicator whether they are similar or not.</p>
</blockquote>
<p>If yes then how is use of clust... | https://datascience.stackexchange.com/questions/107252/conceptual-question-about-cosine-similarity-and-clustering-algorithms-for-word-e |
Question: <p>I would like to understand, how a clustering algorithm can be used (if possible) to identify naturally occurring groups within a data set, prior to building predictive models/model, and to hence improve accuracy of models/model</p>
Answer: <p>In clustering the outcome variable or the response is unknown, ... | https://datascience.stackexchange.com/questions/28639/clustering-algorithm-prior-to-model-building |
Question: <p>I currently do have a dataset of datasets and do want to cluster the data in each dataset. Therefore I want to use a clustering algorithm ...</p>
<p>As such the data in each dataset is a bit special and for example it looks like so:</p>
<pre><code>Datapoints Attribute1 Attribute2 Attribute3
DataPoint1 ... | https://datascience.stackexchange.com/questions/131729/clustering-algorithms-for-datasets-with-enumerable-but-sometimes-unknown-feature |
Question: <p>I have few clustering algorithms tuned having 5 cluster. I want 6th cluster if new data does not belong initial 5 cluster fall in 6th cluster.</p>
<p>6th cluster [ say other category] consist of all data point which does not belong to 5 cluster.</p>
<p>P.S.:- initial whatever data is give is belong those... | https://datascience.stackexchange.com/questions/93264/how-to-add-other-as-one-group-to-clustering-algorithm-inference-pipeline |
Question: <p>I am learning machine learning from scikit-learn and reading its docs.</p>
<p>Clustering clusters groups based on the Euclidean distance and filters them by different ways ex: Gaussian distribution, or mean-shift...etc.</p>
<p>But none of the clustering algorithms cluster samples based on the variation rat... | https://datascience.stackexchange.com/questions/44359/is-there-a-clustering-algorithm-that-can-cluster-time-series-dataset-based-on-va |
Question: <p>Some methods related to manifold-learning are commonly stated as <strong>good-for-visualization</strong>, such as T-SNE and self-organizing-maps (SOM).</p>
<p>I understand that when referring specifically to "visualization" means that the non-linear dimensionality reduction can provide good insights of da... | https://datascience.stackexchange.com/questions/10974/can-i-apply-clustering-algorithms-to-the-result-of-manifold-visualization-method |
Question: <p>Heres the task: I have data I don't know much about. The final task is to build a classifier to classify the samples into a few categories. Some of the categories are pretty clear, we can easily use these as labels for a classifier. But I guess there are more useful categories possible, because right now <... | https://datascience.stackexchange.com/questions/84711/is-there-a-clustering-algorithm-which-accepts-some-clusters-as-input-and-outputs |
Question: <p>I have a problem of clustering huge amount of sentences into groups by their meanings. This is similar to a problem when you have lots of sentences and want to group them by their meanings.</p>
<p>What algorithms are suggested to do this? I don't know number of clusters in advance (and as more data is comi... | https://datascience.stackexchange.com/questions/979/algorithms-for-text-clustering |
Question: <p>A client would like to sort out his filesystem (~ 1,000,000,000 files), which has been fed by numerous workers over the years, each with their own unknown naming convention, e.g.:</p>
<ul>
<li>[DATE]-[CLIENT]-[FILENAME]</li>
<li>[TYPE]-[CLIENT].[DATE][FILENAME]</li>
<li>...</li>
</ul>
<p>Here are four ex... | https://datascience.stackexchange.com/questions/28022/clustering-algorithm-to-sort-filenames |
Question: <p>I'm currently trying to use cluster analysis as a tool for time-series aggregation for a project of mine. The dataset is high-dimensional (386-d), so no chance in assessing the cluster validity visually.</p>
<p>I'm using three different clustering algorithms (k-means++, k-medoids PAM, fuzzy c-means) to fi... | https://datascience.stackexchange.com/questions/52766/should-a-cluster-validity-index-contain-the-same-measures-as-the-clustering-al |
Question: <p>I am trying to find clusters in some data with high noise (see plot below, data <a href="https://pastebin.com/asADpJ0Y" rel="nofollow noreferrer">here</a>).</p>
<p><a href="https://i.sstatic.net/GMnpj.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/GMnpj.png" alt="enter image description her... | https://datascience.stackexchange.com/questions/113940/looking-for-a-clustering-algorithm-for-highly-noisy-data |
Question: <p>I am trying to implement k-means clustering algorithm, but I am confused about calculating the distance and update(move) cluster centroids. For example, let's say that I have 2 features. One of them is <code>weight={2,4,6,8,11,14,21}</code> and the other one is <code>height={4,6,7,8,9,12,14}</code>. So, in... | https://datascience.stackexchange.com/questions/13200/k-means-clustering-algorithm-problems |
Question: <p>I have a database that has information such as Latitude, longitude, plus other information such as sightseeing locations, restaurants and shopping centers, if it's rural or suburb,... It also has grids and centroids for each grid on the map. I need to cluster the area based on similarities, so when someone... | https://datascience.stackexchange.com/questions/114367/best-clustering-algorithm-or-model-for-clustering-areas-on-map |
Question: <p>I have a dataframe with 2 columns of numerical values. I want to apply a clustering algorithm to put all the entries into the same group, which have a relatively small distance to the other entries. But which clustering algorithm can I use, although I do not know how many groups will be formed? It would be... | https://datascience.stackexchange.com/questions/66140/clustering-algorithm-which-does-not-require-to-tell-the-number-of-clusters |
Question: <p>I need to find a good clustering for this data using sci-kit. </p>
<p><a href="https://i.sstatic.net/AZnRG.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/AZnRG.png" alt="enter image description here"></a></p>
<p>KNN is not appropriate as it creates blobs although these data are linearly s... | https://datascience.stackexchange.com/questions/19443/appropriate-clustering-algorithm |
Question: <p>I'm looking for a clustering algorithm that will make cluster depending on a orientation. The DBSCAN algorithm cluster points based on a constant radius :</p>
<p><a href="https://upload.wikimedia.org/wikipedia/commons/thumb/a/af/DBSCAN-Illustration.svg/800px-DBSCAN-Illustration.svg.png" rel="nofollow noref... | https://datascience.stackexchange.com/questions/41520/is-there-an-oriented-clustering-algorithm |
Question: <p>I am performing extensive customer segmentation analysis and so far implemented Gaussian Mixture Models, K-Means, and Hierarchical Clustering. For the most part, the algorithms agree on the structure of the clusters and well as the number (7-8). I would like to know if there is a common method to either...... | https://datascience.stackexchange.com/questions/75923/what-methods-are-available-to-evaluate-similarity-between-different-clustering-a |
Question: <p>I'm looking for a clustering algorithm that clusters objects, by using their pairwise distances, without needing to calculate all pairwise distances.</p>
<p><strong>Normally pairwise clustering is done like this:</strong> (see <a href="https://datascience.stackexchange.com/questions/701/clustering-pair-wi... | https://datascience.stackexchange.com/questions/46950/are-there-algorithms-for-clustering-objects-with-pairwise-distances-without-com |
Question: <p>I use the DCC algorithm to cluster some data.
The whole algorithm is available here, but shortly it is:</p>
<ol>
<li>construct mkNN graph of the data points (the connected components of it are the clusters).</li>
<li>pretrain an Autoencoder for data dimension-reduction.</li>
<li>train the Autoencoder witn ... | https://datascience.stackexchange.com/questions/82847/deep-continious-clustering-algorithm-just-one-output-cluster |
Question: <p>I have done some research on clustering algorithms since for my goal is to cluster noisy data and identify outliers or small clusters as anomalies. I consider my data noisy because of my main feautures can have quite varying values. Therefore, my focus has been on density based algorithms with quite some s... | https://datascience.stackexchange.com/questions/20471/notion-of-cluster-centers-and-cluster-comparison-in-density-based-algorithms |
Question: <p>I have a survey where each question is related to a different 'shopper' type (there are 5 types so 5 questions). Each question is either binary (True/False) or scale based.</p>
<p>IE:</p>
<pre><code>1. Do you like to shop at our physical location store ? (True/False)
2. Do our discounts entice you to sh... | https://datascience.stackexchange.com/questions/65925/best-clustering-algorithm-to-identify-clusters-and-determine-the-closet-cluster |
Question: <p>I'm having a hard time getting kmeans to cluster data effectively. It fails to segment data well even for a simple attribute with 5 categories. I'm aware of DBSCAN, Hierarchical Clustering and GMM. However, just wanted to know if there's any way (visual or otherwise) to narrow down the clustering algorithm... | https://datascience.stackexchange.com/questions/56638/is-there-any-method-to-determine-which-clustering-algorithm-to-use-on-a-particul |
Question: <p>I'm looking for something like K-Means for dividing solid polygons into regions. K-Means clusters discrete points. But I want to cluster (that is, partition) the points of solid polygons.<a href="https://i.sstatic.net/43RD0.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/43RD0.png" alt="expe... | https://datascience.stackexchange.com/questions/56565/are-there-any-algorithms-for-solid-polygon-clustering |
Question: <p>Does anyone could explain in details how heap structure works in Cluster Algorithm?</p>
<p>I am planning to code CURE in Matlab (Clustering using representatives) but, at first, the paper mentions that all points of datasets are considerered as clusters and heap helps to merge new clusters and I do not kn... | https://datascience.stackexchange.com/questions/15116/built-a-heap-in-cluster-algorithm |
Question: <p>I'm analyzing the GDELT dataset and I want to determine thematic clusters. Simplifying considerably, GDELT parses news articles and extracts events. As part of that, it recognizes, let's say, 250 "themes" and tags each "event" it records in a column a semi-colon separated list of all themes identified in t... | https://datascience.stackexchange.com/questions/17109/seeking-appropriate-clustering-algorithm |
Question: <p>I've a list of 1,300 news events, represented by only three terms coming from running LDA topic model on thousands of tweets. Here's some of them as an example:</p>
<pre><code>['manchester,bony,city', 'attack,claims,responsibility', 'police,officers,nypd',
'goal,arsenal,liverpool', 'test,pakistan,sunday'... | https://datascience.stackexchange.com/questions/28711/cluster-algorithm-to-group-events-in-more-general-domains |
Question: <p>I'm relatively new to cluster analysis, and I'm exploring options for general-purpose, non-hierarchical, strict partitioning of data based on a pre-computed <span class="math-container">$N\times N$</span> pairwise similarity matrix. The matrix must be computable from an arbitrary user-specified (i.e., non... | https://datascience.stackexchange.com/questions/112186/which-clustering-partitioning-algorithms-can-operate-on-arbitrary-pairwise-simil |
Question: <p>There are many metrics to evaluate clustering algorithm like Calinski-Harabaz Index, Dunn index, Rand index, etc. Are there any advantage of using Dunn index over other metrics for evaluating clustering algorithm (K-means in particular)? If yes, what are the advantages and disadvantages?</p>
Answer: <p>Th... | https://datascience.stackexchange.com/questions/27978/what-is-the-advantage-of-using-dunn-index-over-other-metrics-for-evaluating-clus |
Question: <p>I'm trying to figure out how much complexity I can get away with and am looking for model recommendations.</p>
<p>I have transactional data on hand - the features being customer id, customer balance, transaction amount, transaction date/time, receiver id (possibly a company), company_type (if a company).</... | https://datascience.stackexchange.com/questions/124702/graph-clustering-algorithms-when-both-nodes-and-edges-have-features-numerical |
Question: <p>Lets give an example
<code>X: 1 2 3 4 5
Y: .9 .91 .92 .93 .94
Z: 20 36 999 211
M. 4000 3456 1 0</code></p>
<p>When I have such dataset, Which clustering algorithm to choose ? Also, How to interpret the results after clustering ?
Meaning: How to feed 4D dataset into cluster.</p>
<p>I found DBSCAN availabl... | https://datascience.stackexchange.com/questions/17997/which-clustering-algorithm-to-use-for-unique-4dimension-dataset-before-feeding-t |
Question: <p>For vanilla K-Means clustering algorithm I know that the time complexity is:</p>
<blockquote>
<p>Time complexity: O(tknm),</p>
</blockquote>
<p>where n is the number of data points, k is the number of clusters, and
t is the number of iterations, m is the dimensionality of the vectors. </p>
<p>So, when... | https://datascience.stackexchange.com/questions/19042/what-is-the-space-time-complexity-of-mini-batch-k-means-clustering-algorithm |
Question: <p>I am trying to implement the Brown Clustering Algorithm.</p>
<p><strong>Paper details: "Class-Based n-gram Models of Natural Language" by Brown et al</strong></p>
<p>The algorithm is supposed to in <code>O(|V|k^2)</code> where <code>|V|</code> is the size of the vocabulary and k is the number of clusters... | https://datascience.stackexchange.com/questions/896/how-to-implement-brown-clustering-algorithm-in-ovk2 |
Question: <p>I have a very limited background in data science and dataset processing and I was hoping I could get some help here. I am doing some work that requires clustering certain data points having <span class="math-container">$(x, y)$</span> position values and associated weight <span class="math-container">$W_i$... | https://datascience.stackexchange.com/questions/50933/looking-for-an-algorithm-which-does-max-sum-clustering |
Question: <p>I've a dataset and I want to implement K-Means, Fuzzy C Means, Gaussian Mixture Model, Spectral Graph. After that, I want to see the clusters that I get from different methods. What is the proper way to do that? Or should I only stick one algorithm and try to maximize correctness of that clustering?</p>
A... | https://datascience.stackexchange.com/questions/81804/how-to-apply-multiple-clustering-algorithms-to-same-dataset-and-make-comparison |
Question: <p>I am working with a mixed data set, corresponding to TV consumption data, with the aim of reducing the number of features to only those relevant to detect TV consumption patterns (or consumption groups) using clustering.</p>
<p>The dataset is composed of about 20 dimensions and 2.000.000 samples for 1 day ... | https://datascience.stackexchange.com/questions/93912/how-can-i-reduce-the-number-of-dimensions-using-a-clustering-algorithm-in-a-mixe |
Question: <p>I have a large labeled dataset with 29 classes. Is is possible to use a clustering algorithm (like k-means) in this dataset, or it's not possible since clustering algorithms are unsupervised ? </p>
Answer: <p>You can do many things:</p>
<ul>
<li>Forget about the labels: just use the features that are not... | https://datascience.stackexchange.com/questions/31975/clustering-a-labeled-data-set |
Question: <p>We are trying to run J48 on a classified data set. Our class attribute has two possible values ( 0,1) when running J48 the tree terminates at the very first node and doesnt process any further.</p>
<p>Instead of considering (0- false) as the starting point of J48. How can we consider running J48 by select... | https://datascience.stackexchange.com/questions/6316/weka-class-attribute-suggestion |
Question: <p>i create a decision tree model using c4.5 algorithm. After create the model, i evaluate model using 10 fold cross validation and classify model using test data to get accuracy. And then I run prune tree with REP. </p>
<p>My question is what data should i use to compare accuracy (after prune and before pru... | https://datascience.stackexchange.com/questions/10115/pruning-tree-using-rep |
Question: <p>Suppose we use a decision tree to predict if a bank customer can pay back a credit. So it is a two class classification problem. Now we can make two mistakes:</p>
<ul>
<li>$\alpha$ error: The customer can back the credit, but we predict he can't.</li>
<li>$\beta$ error: The customer can't pay back the cre... | https://datascience.stackexchange.com/questions/11379/how-can-decision-trees-be-tuned-for-non-symmetrical-loss |
Question: <p>I'm doing some ADA boosting with Decision stumps and in inducing a binary classifying decision stump, i'm finding both leaf nodes to have a positive value. Can this be the case? Is this possible?</p>
Answer: <p>What is the overall response rate? If it's low (even 15-20%) it may be difficult to find decisi... | https://datascience.stackexchange.com/questions/11752/decision-stumps-with-same-value-leaf-nodes |
Question: <p>For example I have the following data structure:</p>
<pre><code>user: Chris
age: 32
income: 60.000
basket value: 45
</code></pre>
<p>I want predict the basket value, and my features are the age and income.</p>
<p>With a linear regression I get a regression function as the result of the fitting for examp... | https://datascience.stackexchange.com/questions/24167/forecasting-how-decision-tree-work |
Question: <p>I am reading the gini index definition for decision tree: </p>
<pre><code>Gini impurity is a measure of how often a randomly chosen element from the set would be incorrectly labeled if it was randomly labeled according to the distribution of labels in the subset.
</code></pre>
<p>This seems to be the s... | https://datascience.stackexchange.com/questions/31535/difference-between-impurity-and-misclassificaton |
Question: <p>See5 / C5.0 is Data Mining Tools available from <a href="https://www.rulequest.com/see5-info.html" rel="nofollow noreferrer">rulequest</a></p>
<p>I want to compile C50 for Linux, preferably for CentOS 6.x, but I am unable to compile. I have also tried on Ubuntu, but not success there as well. </p>
<p>I h... | https://datascience.stackexchange.com/questions/47309/compile-see5-c50-gpl-edition |
Question: <p>I've been fiddling with weka's J48 decision tree implementation (C4.5). My goal is to implement cost complexity prunning using weakest link cut method. Basically my algorithm iteratively prunes the tree creating trees with fewer nodes from the previous ones (<span class="math-container">$ T_0 > T_1 >... | https://datascience.stackexchange.com/questions/48789/number-of-iterations-for-minimal-cost-complexity-prunning |
Question: <p>Say I have AttributeA that can take values A1, A2, A3, AttributeB that can take values B1, B2, B3, etc. and I know ahead of time that my classification table looks like</p>
<p>AttributeA | AttributeB | AttributeC | Classification</p>
<p>A1 | B1 | anything | Class 1</p>
<p>anything | B2 | anything | Clas... | https://datascience.stackexchange.com/questions/55862/how-should-a-decision-tree-handle-an-attribute-that-can-be-anything |
Question: <p>I have a data set with ordinal features.Each feature might have 6 to 7 levels.
Based on my search for R if you have ordinal data, rpart treats ordinal and nominal differently.
<a href="https://stats.stackexchange.com/questions/94502/decision-tree-splitting-factor-variables">https://stats.stackexchange.com/... | https://datascience.stackexchange.com/questions/58745/ordinal-features-to-decision-tree-in-python |
Question: <p>Decision tree functions are discontinuous functions of the predictors. Have continuous decision trees with smooth transitions been studied? For example, a decision tree in two variables</p>
<pre><code>f(x1,x2) = c1 if x1 < t1 and x2 < t2
c2 if x1 < t1 and x2 >= t2
c3 i... | https://datascience.stackexchange.com/questions/61382/continuous-decision-trees-using-logistic-functions |
Question: <p>I'm working through a decision tree by hand to learn it. From my research, I have found the following three ways of determining which variables to split on:</p>
<ol>
<li>Minimum remaining values - The variable with the fewest legal values is chosen</li>
<li>Degree heuristic - The variable with the most co... | https://datascience.stackexchange.com/questions/63253/what-are-the-ways-to-identify-a-good-attribute-test-while-constructing-a-decisio |
Question: <p>Vague condition: "NumGoals >= 1.23" </p>
<p>Preferred condition: "NumGoals > 1".</p>
<p>Switched normalization off.</p>
<p>Code:</p>
<pre><code>from sklearn.datasets import load_iris
from sklearn.tree import DecisionTreeClassifier, plot_tree
import matplotlib.pyplot as plt
import numpy as np
iris = lo... | https://datascience.stackexchange.com/questions/64450/decisiontreeclassifier-integer-conditions-integer-outcome-variable |
Question: <p>If we have numeric variable, decision trees will use <code><</code> and <code>></code> comparisons as splitting criteria. Lets consider this case : If our target variable is <code>1</code> for even numeric value, and <code>0</code> for odd numeric value. How to deal with this type of variables? How t... | https://datascience.stackexchange.com/questions/71678/numeric-variables-in-decision-trees |
Question: <p>I would like to use algorithm ID3 in order to find a decision tree of my <a href="https://www.kaggle.com/rtatman/chocolate-bar-ratings" rel="nofollow noreferrer">dataset</a>. I would like to see which of the attributes and values lead to the different value of rating (1<= x <= 5). Do you think it is ... | https://datascience.stackexchange.com/questions/74675/decision-tree-on-big-categorical-dataset |
Question: <p>I am trying to create a prediction model by using a decision tree with Turicreate. While my problem does involve numbers, it also involves strings and ultimately I want it to return the string 'true/false'. Are Turicreate decision trees able to process strings as input and output?</p>
Answer: <p>I'm not f... | https://datascience.stackexchange.com/questions/87391/strings-features-in-turicreate-decision-tree |
Question: <p>Standard decision tree algorithms, such as ID3 and C4.5, have a brute force approach for choosing the cut point in a continuous feature. Every single value is tested as a possible cut point. (By tested I mean that e.g. the Information gain is calculated at every possible value.)</p>
<p>With many continuou... | https://datascience.stackexchange.com/questions/18156/how-to-better-discretize-continuous-data-in-decision-trees |
Question: <p>Computational vs intuitionistic or expert-based information gain in decision trees?</p>
<p>This confuses me.</p>
<p>Plenty of literature on how information gain can be used when it's calculated computationally. But what if there's a competing sense of "intuitionistic (or expert-based) information impo... | https://datascience.stackexchange.com/questions/97725/computational-vs-intuitionistic-or-expert-based-information-gain-in-decision-tre |
Question: <p>I want to implement my own version of the CART Decision Tree from scrach (to learn how it works) but I have some trouble with the Gini Index, used to express the purity of a dataset.</p>
<p>More precisely, I don't understand how Gini Index is supposed to work in the case of a regression tree.</p>
<p>The ... | https://datascience.stackexchange.com/questions/35672/gini-index-in-regression-decision-tree |
Question: <p>I was trying to find the original CART paper. I found papers like <a href="https://www.researchgate.net/publication/227658748_Classification_and_Regression_Trees" rel="nofollow noreferrer">https://www.researchgate.net/publication/227658748_Classification_and_Regression_Trees</a> which experimented on CART ... | https://datascience.stackexchange.com/questions/106614/where-can-i-find-the-original-cartclassification-and-regression-trees-publishe |
Question: <p>Imagine a set of products in a store, with all the different attributes assigned to them - some of these hierarchical (e.g. categories), and some not (e.g. brand), but none of them continuous (if that is even important here). For each product, we know how much (in money-value) we've sold last year, and how... | https://datascience.stackexchange.com/questions/110370/identifying-subsets-of-values-significant-to-the-total-sum |
Question: <p>After training and testing the decision tree model, it always gives me the same outcome on any given data. Im talking about a binary classification yes or no.
Basically when I do predict(fit_model, newdata=new_data) I always get no regardless the data I give. The model is quite simple and I can compute the... | https://datascience.stackexchange.com/questions/111697/decision-tree-question-in-r |
Question: <p>There are numerous ways to induce an oblique decision tree in the decision tree induction domain, such as using a support vector machine to determine the best hyper-plane. However, is it possible to generate an oblique decision tree for regression? I discovered that the majority of existing literature has ... | https://datascience.stackexchange.com/questions/93520/how-to-implement-an-oblique-decision-tree-for-regression |
Question: <p>I'm new to data science field and interested in performing prediction using clickstream data. In <a href="https://quinonero.net/Publications/predicting-clicks-facebook.pdf" rel="nofollow noreferrer">Practical Lessons from Predicting Clicks on Ads at Facebook</a> paper section 3.1, a method called Decision ... | https://datascience.stackexchange.com/questions/94322/tree-based-feature-transformation |
Question: <p>For neural networks we have the <a href="https://en.wikipedia.org/wiki/Universal_approximation_theorem" rel="noreferrer">universal approximation theorem</a> which states that neural networks can approximate any continuous function on a compact subset of $R^n$.</p>
<p>Is there a similar result for gradient... | https://datascience.stackexchange.com/questions/32796/can-gradient-boosted-trees-fit-any-function |
Question: <p>I am looking through decision trees, and I do not understand what makes each of these methods different. Could someone explain clearly what the difference between these is? Thank you.</p>
Answer: <p>As I understand it, all three want to minimize the false classified data points in your data set. (Logicall... | https://datascience.stackexchange.com/questions/48560/what-is-the-differences-in-the-gini-index-chi-square-and-information-gain-spli |
Question: <p>There are common ways to split a tree in decision trees and all their variants:</p>
<ul>
<li>Gini Index</li>
<li>Entropy</li>
<li>Misclassification</li>
</ul>
<p>Why there is not a method which uses directly AUC or accuracy (or whichever the modeler need) to split the nodes.</p>
<p>Is it because of comm... | https://datascience.stackexchange.com/questions/51039/why-is-not-auc-or-other-metrics-used-for-splitting-nodes-in-decision-trees |
Question: <p>If I come across decision trees, it is a binary tree with predicates internal nodes.
How often do we use m-ary decision trees?
Is there any combination of m-ary and binary decision tree, e.g. first level of the tree is binary and second level of the tree consists of m-ary?
Same question arises for Random F... | https://datascience.stackexchange.com/questions/62151/how-often-do-we-use-m-ary-decision-trees |
Question: <p>According to this post, the time on a 24-hour clock should be decomposed into separate periodic components:</p>
<p><a href="https://ianlondon.github.io/blog/encoding-cyclical-features-24hour-time/" rel="nofollow noreferrer">https://ianlondon.github.io/blog/encoding-cyclical-features-24hour-time/</a></p>
... | https://datascience.stackexchange.com/questions/72965/do-i-need-to-transform-time-with-sin-cos-if-im-using-decision-tree-algorithms |
Question: <p>To introduce, I am a novice in ML techniques. I recently had to write a <code>scikit-learn</code> based decision tree classifier to train on a real dataset. Someone suggested me that I must run mu model several thousand times and plot the accuracies on a graph. Here's the rub: I manually ran it around 20 -... | https://datascience.stackexchange.com/questions/37389/does-running-a-decision-tree-classifier-several-times-help |
Question: <p>Could you please explain what the hypothesis space for decision tree learning look like?</p>
<p>And what is the cardinality of this space?</p>
Answer: <p>As per Tom Mitchell's,</p>
<p>".....For example, consider the space of
hypotheses that could in principle be output by the above checkers learner. Thi... | https://datascience.stackexchange.com/questions/73941/what-is-the-hypothesis-space-of-decision-tree-learning |
Question: <p>I'm trying to follow the suggested outline form implementing ID3</p>
<pre><code># Step 1- Calculate MC (Message Conveyed) for the given dataset (let us call it file TF) in reference to the class attribute
# MC(TF) = -p1*log2(p1) - p2*log2(p2)
# For n classes MC(TF) = -p1log2(p1) - p2*log2(p2)-...-pn*log... | https://datascience.stackexchange.com/questions/104516/how-to-implement-id3 |
Question: <p>For example, a drug prediction problem using a decision tree. I trained the decision tree model and would like to predict using new data.</p>
<p>For example:</p>
<pre><code>patient, Attr1, Attr2, Attr3, .., Label
002 90.0 8.0 98.0 ... ? ===> predict drug A
</code></pre>
<p>How can I calcu... | https://datascience.stackexchange.com/questions/11171/decision-tree-how-to-understand-or-calculate-the-probability-confidence-of-pred |
Question: <p>I am curious if ordinal features are treated differently from categorical features in decision tree, I am interested in both cases where target is categorical or continuous.</p>
<p>If there is a difference, could you anybody point to good source with explanation and any packages (R or Python) supporting i... | https://datascience.stackexchange.com/questions/14025/ordinal-feature-in-decision-tree |
Question: <p>Can anybody please explain the affect of multicollinearity on Decision Tree algorithms (Classification and regression).
I have done some searching but was not able to find the right answer as some say it affects it and others say it doesn't.</p>
Answer: <p>Desicion trees make no assumptions on relationshi... | https://datascience.stackexchange.com/questions/31402/multicollinearity-in-decision-tree |
Question: <p>Is it possible to do hard-coded decision tree on some variables and random forest / something on the remaining ones?</p>
<p>The situation seems that for some variables it's possible to draw strong empirical assumptions, but for others their "relative importance" seems more random.</p>
<p>So e.g.<... | https://datascience.stackexchange.com/questions/97748/is-it-possible-to-do-hard-coded-decision-tree-on-some-variables-and-random-fores |
Question: <p>I read in a blog that the decision tree has this disadvantage:</p>
<blockquote>
<p>Not fit for continuous variables</p>
</blockquote>
<p>If this is true, then why?</p>
Answer: <p><strong>Continuos Variable in training data (X)</strong>
If you look at decision trees they try to split data based on categori... | https://datascience.stackexchange.com/questions/31491/disadvantage-of-decision-tree |
Question: <p>I am interested in finding out how decision trees chose the order in which they split. I understand that splitting is based in information gain. The attribute with the lowest information gain is chosen as the root node.</p>
<p>If I had a data set with columns:</p>
<ol>
<li>credit standing</li>
<li>age</l... | https://datascience.stackexchange.com/questions/24831/decision-tree-ordering |
Question: <p>We are working on a physiological marker predictor using hospital patient data. We use a boosted decision tree-type algorithm, which seems to be very sensitive to the noise in the training data. Would it be fair to say the NN's are less sensitive to noisy data than decision trees?</p>
Answer: <p>It is not... | https://datascience.stackexchange.com/questions/119907/noisy-data-robustness-nn-vs-decision-tree |
Question: <p>I have a dataset with 20 features(columns that is). I create a few models pairs with a subset of these parameters.</p>
<p>For example: If I have 6 columns (named A, B, C, D, E, F) with 10k lines of data, one of model in the pair will have (A, B, C) with all 10k lines of data and the other (A, B, C) with m... | https://datascience.stackexchange.com/questions/37660/comparing-parameter-importance-across-models |
Question: <p>I read <a href="https://www.researchgate.net/post/How_to_compute_impurity_using_Gini_Index" rel="nofollow noreferrer">https://www.researchgate.net/post/How_to_compute_impurity_using_Gini_Index</a></p>
<p>I understand why choosing smallest gini index, but how do I come up with different candidate splits in... | https://datascience.stackexchange.com/questions/32129/how-to-come-up-with-the-splitting-point-in-a-decision-tree |
Question: <p>in figure B), there are leaves (gray boxes) with 3 values, for example, the leftmost leaf has 19.3 (28/8.7%) as its values, the 3 values are (19.3, 28, and 8.7%). </p>
<p>19.3 is the average value of the instances that reach that leaf
28 is the number of instances (out of the 209 total instances)
what doe... | https://datascience.stackexchange.com/questions/58842/what-do-the-percentages-in-the-leaves-of-a-decision-tree-represent |
Question: <p>Consider the following Decision table :
<a href="https://i.sstatic.net/jknFz.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/jknFz.jpg" alt="enter image description here"></a></p>
<p>The following is the reduction process of this table :
<a href="https://i.sstatic.net/OzaxQ.jpg" rel="nofo... | https://datascience.stackexchange.com/questions/66352/decision-table-reduction |
Question: <p>I have the following binary Decision Tree:</p>
<p><a href="https://i.sstatic.net/YopbR.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/YopbR.png" alt="enter image description here" /></a></p>
<p>Can you please explain how can I report this tree to a person who only understands probabilities?... | https://datascience.stackexchange.com/questions/82102/using-gini-index-how-to-calculate-the-probability-of-correctly-classifying-a-ne |
Question: <p>My decision tree entropy is coming more than 1 when I'm calculating it manually. Not sure if there's some calculation error.</p>
<p>Trying it on the <a href="https://archive.ics.uci.edu/ml/datasets/iris" rel="nofollow noreferrer">Iris dataset</a>.</p>
<p>If I split on sepal length at 6.5 cm, my split looks... | https://datascience.stackexchange.com/questions/107647/getting-entropy-in-decision-trees-more-than-1 |
Question: <p>I'm confused by an example I have come across on entropy.</p>
<p>In a decision tree, we have after a split on some particular feature, the following subset of our training data. What is the resultant entropy of the target feature in this set?</p>
<p><a href="https://i.sstatic.net/VL6iT.png" rel="nofollow ... | https://datascience.stackexchange.com/questions/109821/resultant-entropy-of-the-target-feature-example |
Question: <p><a href="https://i.sstatic.net/76Ot9.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/76Ot9.jpg" alt="enter image description here" /></a></p>
<p>how can I apply decision tree classification to get malnutrition status(target variables are wasting, stunting,overweight,underweight)</p>
Answer:... | https://datascience.stackexchange.com/questions/122304/decision-tree-classification-code-for-categorical-data |
Question: <p>I came across the concept of <em>Information Gain</em> in decision trees.</p>
<p><a href="https://i.sstatic.net/zAFkb.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/zAFkb.png" alt="IG" /></a></p>
<p>Where <span class="math-container">$I(D_p)$</span> is the information of the parent node and... | https://datascience.stackexchange.com/questions/126120/why-is-it-called-information-gain-and-not-information-loss |
Question: <p>I read that decision trees (I am using scikit-learn's classifier) are robust to outlier. Does that mean that I will not have any side-effect if I choose not to remove my outliers? </p>
Answer: <p>Yes.
Because decision trees divide items by lines, so it does not difference how far is a point from lines.</p... | https://datascience.stackexchange.com/questions/37394/are-decision-trees-robust-to-outliers |
Question: <p>I asked this in a reply to an answer to another of my questions; but I think this merits its own question since I couldn't find an answer, and it's a pretty interesting question on its own.</p>
<p>Suppose we construct a decision tree for classification based on the Gini impurity function. Can we prove tha... | https://datascience.stackexchange.com/questions/94004/proof-that-gini-impurity-in-a-decision-tree-is-monotone-decreasing |
Question: <p>What exactly is the difference between model-based boosting and gradient boosting? For an intro to model-based boosting see <a href="https://cran.r-project.org/web/packages/mboost/vignettes/mboost_tutorial.pdf" rel="nofollow noreferrer">https://cran.r-project.org/web/packages/mboost/vignettes/mboost_tutori... | https://datascience.stackexchange.com/questions/55128/difference-between-model-based-boosting-and-gradient-boosting |
Question: <p>How is AdaBoost different from a Gradient Boosting algorithm since both of them use a Boosting technique?</p>
<p>I could not figure out actual difference between these both algorithms from a theory point of view.</p>
Answer: <p>Both AdaBoost and Gradient Boosting build weak learners in a sequential fashio... | https://datascience.stackexchange.com/questions/39193/adaboost-vs-gradient-boosting |
Question: <p>I understand boosting is a sequential learning technique and it use the prediction from previous model as a dataset for new model ,after adding weight to the misclassified data points.
The point which was not clear how the weights are added for misclassified ones and diminished for the correctly classifie... | https://datascience.stackexchange.com/questions/61333/ensemble-techniques-boosting |
Question: <p>I have a classification problem.
In gradient tree boosting I read that-<br>
1. Initially a weak learner is fitted on the entire training dataset.<br>
2. Output of each training row is obtained. In my case it will be {0,1}.
3. Now, the second classifier will train on the residual of the prediction i.e {ini... | https://datascience.stackexchange.com/questions/32952/gradient-tree-boosting |
Question: <p>In your algorithms, when you use Gradient Boosting, do you prefer RandomSearchCV or GridSearchCV in order to optimize your hyperparameters ?</p>
<p>Thanks for sharing your experience.</p>
Answer: <p>I think it depends on the size of your multi dimensional grid. If it is small, then you can afford to be e... | https://datascience.stackexchange.com/questions/46120/gradient-boosting-randomsearchcv-or-gridsearchcv |
Question: <p>Can someone exactly tell me how does boosting as implemented by LightGBM or XGBoost work in real case scenerio. Like I know it splits tree leaf wise instead of level wise, which will contribute to global average not just the loss of branch which will help it learn lower error rate faster than level wise tr... | https://datascience.stackexchange.com/questions/106267/example-for-boosting |
Question: <p>Since boosting is sequential, does that mean we cannot use multi-processing or multi-threading to speed it up? If my computer has multiple CPU cores, is there anyway to utilized these extra resources in boosting?</p>
Answer: <p>You can estimate in parallel each of the weak learners. For example, searching... | https://datascience.stackexchange.com/questions/44123/can-parallel-computing-be-utilized-for-boosting |
Question: <p>I have been working on ensemble learning and I came across this doubt that unlike other ensemble learning algorithms like voting classifier a can we only use one classifier with boosting.</p>
Answer: <p>Boosting typically only use one algorithm as it's base learner (almost exclusively decision trees). How... | https://datascience.stackexchange.com/questions/56098/can-we-use-boosting-algorithms-like-adaboost-and-gradient-boosting-with-only-one |
Question: <p>I have some questions I don't really understand regarding the Gradient Boosting algorithm with Decision Trees:</p>
<ul>
<li><p>Does the initial value matter as <span class="math-container">$\hat{y}$</span> or could you pick any, f.e between 0 and 1?</p>
</li>
<li><p>Why do we fit the tree to the pseudo-res... | https://datascience.stackexchange.com/questions/126108/gradient-boosting-why-pseudo-residuals |
Question: <p>i am testing gradient boosting regressor from sklearn for time series prediction on noisy data (currency markets). </p>
<p><a href="https://scikit-learn.org/stable/modules/generated/sklearn.ensemble.GradientBoostingRegressor.html" rel="nofollow noreferrer">https://scikit-learn.org/stable/modules/generated... | https://datascience.stackexchange.com/questions/63313/best-way-to-regularize-gradient-boosting-regressor |
Question: <p>I have a conceptual question. My understanding is, that Random Forest can be applied even when features are (highly) correlated. This is because with bagging, the influence of few highly correlated features is moderated, since each feature only occurs in <em>some</em> of the trees which are finally used to... | https://datascience.stackexchange.com/questions/71410/boosting-with-highly-correlated-features |
Question: <p>Can anyone explain me the basic difference between bagging and boosting and which technique can be used in which scenario?</p>
Answer: <p><strong>Bagging</strong>: Also known as Bootstrap Aggregation is an ensemble method. First, we create random samples of the training data set (sub sets of training data... | https://datascience.stackexchange.com/questions/39577/difference-between-bagging-and-boosting |
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