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Questions tagged [algorithms]

An unambiguous list of computational steps involved in finding a solution to a class of problems.

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Product Packaging Problem: Measuring by pieces vs. Measuring by grams

I am helping a friend with his chicharon (pork cracklings) business. Initially, each selling package contains 50 grams of the product but he changed his mind and wanted 20 pieces instead for each ...
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1answer
25 views

What's this class of algorithms called: (entire training dataset, new input) -> output?

Supervised machine learning algorithms normally work by preprocessing a training dataset and outputting a compact model (e.g. a bunch of regression coefficients) that can quickly give an approximate ...
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25 views

Statistically determining the median of a data set via quantiles of a sample

I was thinking of algorithms for statistically determining the median of a large data set. To estimate the complexity of my idea I need the following Probability: I have a dataset $\left\{x_i \right\}...
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1answer
62 views

why has author divided by 1.5 in hands on machine learning with scikit learn

I am reading Hands-On Machine Learning with Scikit-Learn and TensorFlow (76/718), and the author is talking about dividing the dataset into a test set which i follow, but then goes on to talk about ...
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1answer
14 views

ML Sampling question - Can I increase sample size of current dataset with older copies that have changed over time

I am working on a multinomial machine learning algorithm that labels stocks with buy/sell signals. My code updates with the most recent quantitative data about the stocks daily, so obviously the data ...
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12 views

Weighted score algorithm

I'm trying to come up with the solution for a recurrent problem in many different industries. I have an idea of what can be done, but I'm struggling to model mathematically. Here's an example: ...
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2answers
51 views

What is the difference between deep and shallow machine learning?

There's a lot of information about deep learning but what features should an algorithm have for it to be classified as deep or shallow? Is shallow only related to neural networks?
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31 views

Predict Data Using Similar Dataset (Machine Learning Algorithm)

I have a dataset of temporary streamflow monitoring data, with flows recorded every 5 minutes for a period of several months to a few years for several hundred streams across the country. I also have ...
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1answer
17 views

Prior/degree of belief/degree of lack-of-information/algorithms/complexity

For a long time I had a bit of difficulty understanding what "degree of belief" means. Recently I had some thoughts about it and I wonder if they make any sense, or is there some literature about ...
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14 views

Can we mix the algorithm?

The question comes from when I was wondering about the cross-validation, finding out the best algorithm. Then I got the question like if this model did a better job than the other, can the ...
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12 views

Algorithms for combining Bayesian networks? [closed]

Are there any algorithms for combining multiple Bayesian networks? For example, let's say I have 5 variables A, B, C, D and E, and I build 5 Bayesian networks on different random subsets of these, let'...
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Stacking Algorithms - Should Certain Algorithms Not Be Used In Conjunction

Are there any reasons why one wouldn't want to use certain algorithms together in stacking? For example, if I decided to use an SVM and a LogisticRegression classifier and were considering adding a ...
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How does Kamada & Kawai Force Directed layout algorithm interpret negative edge weights?

In Cytoscape, the Kamada & Kawai Force Directed layout algorithm is able to take negative weights between edges. Does anyone know how it's actually using the sign of these? Is it forcing ...
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Which algorithm(s) to use for quote price recommendations based on win/loss percentages by x date range?

I have a problem I'm trying to solve and was hoping someone smarter and more experienced may be able to help me out. Let me describe the problem. Thanks for any help in advance. My company provides ...
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1answer
62 views

Multi-class Decision Forest vs Multi-class Decision Jungle

guys. I have been learning about machine learning using Azure ML service from Microsoft and my team and I have seen that there are some multi-class decision algorithms, the Forest and Jungle are ...
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0answers
7 views

Ordered aggregated choices given users preferences

I have an issue creating an ordered list by preferences. Let's say I have 3 users (u1, u2, u3) and 10 topics (t1,...,t10). Each ...
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29 views

Cross - entropy for two variables with different prob. distributions

Let us say that we have given two random variables with different prob. distributions: A = [0.1, 0, 0.5, ...] B = [0.3, 0.1, 0.03, ...] What should I do when I want to compute the reformulated cross-...
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1answer
21 views

For a specific dataset do all the features have the same importance across different algorithms?

I wonder if by implementing a feature selection technic using training with a specific algorithm you can select the feature you need to use with other algorithms also. To be more specific after I ...
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2answers
65 views

Deep Neural Network visualization on multi dimension datasets [closed]

I have seen the PlayGround of Tensorflow. But it is using only 2D values which means only 2 inputs are taken. I have 7 inputs and the output is only 1. See the datasets sample: ...
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Epsilon from Bivariate Normal Distribution [duplicate]

I came across the following example from a book. I am given a dataset generated from a bivariate normal distribution: Among the data, there are missing values for the last 20 of x2i (but not for x1i)....
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28 views

Computing Wassertein Distance

For two probability measures $\mu$ and $\nu$, the Wassertein Distance is defined as $$W_p (\mu , \nu) = \left[ \inf\limits_{\gamma \in \Gamma} |x-y|^p \, d\gamma (x,y) \right] ^{\frac{1}{p}} \, , $$ ...
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Question about PyTorch tutorial

In this PyTorch tutorial the backprop to compute gradients is shown with the following code: ...
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1answer
60 views

Questions about a k-means variant : recompute centroids after each point is reasigned

I have a variant of k-means, where the points are reassigned incrementally and I have a few questions about it. Each time we reassign a point (we move the point from cluster $C_1 $to $C_2$), we ...
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1answer
53 views

Machine learning algorithm test/evaluation sample size

I have recently implemented a machine learning algorithm as a part of a new credit risk scoring system. I would now like to evaluate the accuracy/performance of the algorithm when used in a "real ...
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1answer
56 views

Comparing two algorithms. Paired t-test, independent test or mixed effect linear regression

I have two algorithms running on 100 benchmark instances. I want to test if there are significant differences in their mean average error. A significant part of those two algorithms is not ...
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1answer
26 views

prerequisites to algorithms and then to python and Machine Learning

I spent the last 5 months studying full-stack web development using the MERN stack, that is (MongoDB, Express, React and NodeJs). Now that I have seen the full picture of what I would be doing ...
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1answer
26 views

How to quickly apply an algorithm with enough understanding

Let me take an explicit example.(the answer should be universal for any algorithm) I want to group cities with similar average income together I want to use dbscan to do this.(R/python/javascript/...
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1answer
26 views

DECISION TREE : How to calculated for repeat decision noded such as this picture (C5.0 Algorithm -Decision tree)

I confused about decision tree such as this picture why repeat decision node.Could you please explain that decision tree. thank you
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1answer
32 views

Comparing Supervised ML algorithms in R on same data set

I've recently embarked on my data science journey, and I've therefore also started a data science course. In this course, we've received an assignment asking us to model a data set using different ...
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1answer
18 views

Detecting a series of measurements

This is somewhat nonstandard: My input is a series of values (integers or reals), and my goal is to decide if this series is likely to be a series of measurements of some unknown phenomenon (be it an ...
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0answers
26 views

ranking metric for a specific use case

I am trying to find the best "ranking metric" for my problem but could not find any existing suitable metric, can someone help. I'm interested in information retrieval. For item there is a "...
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1answer
8 views

Manber's graph-partitioning algorithm implementation

I'm having trouble understanding a part of Manber's graph-partitioning algorithm, presented in A Text Compression Scheme that Allows Fast Searching Directly in the Compressed File. Generally speaking ...
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2answers
31 views

How do I check the validity of a set of inequality constraints? [closed]

I have a table of inequality constraints, each with an "x < y" relation. How can I check this table for contradictory logic such as a < b, b < c, c < a? For example ...
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2answers
97 views

The Universal Approximation Theorem vs. The No Free Lunch Theorem: What's the caveat?

The universal approximation theorem: A neural network with 3 layers and suitably chosen activation functions can any approximate continuous function on compact subsets of $R^n$. The no free ...
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2answers
51 views

Is there a clustering algorithm that maximizes average silhouette? If not, why not?

The average silhouette index of a clustering of data seems to be used to determine the hyper parameter $k$ (i.e. number of clusters) in clustering algorithms like $k$-means. Is there an algorithm that ...
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0answers
14 views

What are the simple methods to do an unsupervised cluster to stock return time series?

I am a student in finance and I am working on my thesis project. I am interested in doing a clustering to stock time series. I first read the paper 'Time-series clustering – A decade review' from ...
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Prediction problem- Build model using 6 months data and predict on one month data?

I have a data set which contains site usage behavior of users over a period of six months. It contains data about: Number of pages viewed Number of unique cookies associated with each user Different ...
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0answers
18 views

Optimizing a sequence of events on a variable conditional on the event

I'm trying to understand how I would approach a problem aiming to optimize a sequence of events to maximize another variable. For example, say I start selling a t-shirt at multiple stores, where each ...
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41 views

Optimal Sequence Problem

Lets says I have 100 people that like to buy item x. They ask me to send them a message every time I have x available to sell. Of the 100 people that like to buy item x: 1) Some people will pay more ...
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6 views

Grouping by equivalent path length

I have a collection of an arbitrary number of discrete "path lengths". I'm interested in discovering some automated (preferably Excel or C++/C#/Java code rather than Matlab or similar) method of ...
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45 views

Efficient linear regression given columns of A rather than rows of A

I'm analyzing a large problem with a large $N \times M$ data matrix $A$, where $N$ is the number of observations, $M$ is the number of explanatory variables, and $N \gg M$. I'd like to perform single-...
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1answer
31 views

How can I use patterns from data analysis to make a predictive machine learning model?

I'm trying to make a predictive model that can predict how well a product will sell in the future based on certain parameters. I've made some visualizations showing the relationship between the data. ...
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1answer
49 views

What are some good canned classifiers for high-dimensional data with probablistic labels, besides neural nets?

I've got a classification problem where my labels are $N\times4$ matrices of probabilities of class membership, and I've got about 1800 covariates. The covariates are mostly granular, in the sense ...
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1answer
35 views

Cross Validation in application of clustering on a collection of similarly behaving time series

I'm trying to understand how and at which point can one apply Cross Validation for time series data. If i'm not wrong CV increases generalisation so that our model has less bias in case the data is ...
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Multivariate fixed point iteration: the wrt variable on both sides of update equation and not are different?

I try to understand more about the update in multivariate fixed point iteration. I saw the examples where the updates have the same variable (the wrt. variable of partial differentiation) on both ...
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0answers
17 views

Optimize function on two stages

I have a non-linear cost function (which I do not know its analytical derivative and it is pretty hard to be computed). The function takes 8 parameters. I need to minimize this function using some ...
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1answer
40 views

Given list symptoms and diseases - how to find similar symptoms based on data

I have a dataset of case studies like that: Gender ; Age ; Symptom ; Condition M ; 20 ; Fever ; Flu F ; 29 ; Arm pain ; Trauma F ; 40 ; Fever ; Cancer M ; 90 ; ...
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2answers
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Is there an algorithm for listing all/minimum admissable sets in a graph that satisfies the backdoor criterion in Causal Inference?

I would like to know if there exists an algorithm for finding all/minimum admissible sets in a graph that satisfy the backdoor criterion as defined by Judea Pearl in his book Causality (Please see ...
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1answer
32 views

Algorithm for selecting largest possible value, when observing online sequence of unknown distribution?

I have been trying to devise an algorithm for a problem that's been bugging me for a while. For some weird reason I haven't been able to find any mention of this problem in the literature, so far. I ...
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1answer
66 views

Is there a (matrix) operation that can count elements in vector pairs?

For two vectors $x \in \{0, 1, 2\}^{n}$ and $y \in \{0, 1, 2\}^{n},$ I need to generate a matrix $C\in \mathcal{R}^{3\times3}$ where $C_{i,j}$ equals the number of indexes $t$ where $x[t]=i$ and $y[t]...