Questions tagged [sparse]

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How to calculate dataset and feature sparsity/density

I have a dataset with 8 features and 30,000 samples but which is probably a sparse sampling. I would like to quantify how sparse or dense the dataset and individual features are, as described in the ...
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Techniques for classification AI with sparse labels

I want to create an AI to classify images with a large set of labels (1000+ labels). However, the labels in the data set are correct but each image is not fully labelled. This means that each image's ...
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Regression with high dimensional sparse boolean predictors

Suppose I have a continuous y response variable and a very large matrix of boolean sparse predictor variables X. What would be the best regression method to use?
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What exactly is activity sparsity and why is it beneficial?

I have been reading about weight sparsity and activity sparsity with regard to convolutional neural networks. Weight sparsity I understood as having more trainable weights being exactly zero, which ...
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Suggestions for binary time-series-classification model for small dataset

Hopefully I´m at the right place for my question: I´m looking for suggestions for models to use to classify multivariate time series. I´m trying to find a way of classifying the behaviour of motors ...
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2 votes
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490 views

Best metric and hyperparameters in dimension reduction with UMAP for binary sparse data

I am playing with a dimensionality reduction step prior to clustering for a pretty large sparse binary matrix of almost 3000 columns and 50k rows. My idea is to embed the 3000 dimensions into a two-...
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Linear regression on sparse matrix?

I have a matrix with sparse data. A small extract from it is seen below. The columns represent years and the rows represent different race tracks. The feature values are velocities on that specific ...
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Dictionary learning for image classification

I'm wondering if the approach I'm thinking of could even work. I want to use dictionary learning for image classification. The first step would be to learn the dictionary from a set of similar yet ...
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1 vote
1 answer
298 views

Predicting high frequency sparse time series data in python

I have a dataset of a couple of EV charging stations (10 min frequency) over 1 year. This data consists of lots of 0's, since there is no continuous flow of cars coming to charge but rather ...
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3 answers
644 views

How to create a big data frame in Python

I have a sparse matrix, $X$, created by TfidfVectorizer and its size is $(500000, 200000)$. I want to convert $X$ to a data frame but I'm always getting a memory error. I tried ...
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1 vote
1 answer
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Predicting sparse time series data

I have a dataset of a couple of EV charging stations (10 min frequency) over 1 year. This data consists of lots of 0s, since there is no continuous flow of cars coming to charge, but rather ...
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61 views

How to work with input which is a combination of metadata+ vectorized text data + image pixel data to build a Regression Model (predict views)?

There are 4 datasets (all in csv format), each has a uniqueID column by which each record can be identified. Image and text datasets are dense datasets.(need to be converted to ndarray). Can someone ...
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Why do my target labels need to begin at 0 for sparse categorical cross entropy to work?

I'm following a guide here to implement image segmentation in Keras. One thing I'm confused about are these lines: ...
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1 answer
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Anomaly detection on sparse categorical data

I have a big dataset with a column "clientid" and a categorical column "choice". I want to find out what are the clients that have strange combinations of choices (less frequent ...
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1 answer
63 views

Correlation/distance between sparse vectors

I am looking for a metric for comparing gene count tables. These are long columns of data (a few millions genes by a few dozen samples), with all non-negative entries, about 90% of which are zeros. ...
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1 vote
1 answer
489 views

unsupervised anomaly detection on sparse data

Given that I have a very sparse data matrix with continuous features, like this dataframe for example ...
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1 answer
203 views

Softmax regression cost function code [closed]

I really do not understand what does this code do M = sparse.coo_matrix(([1]*n, (Y, range(n))), shape=(k,n)).toarray() The code is related to calculating the ...
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Autoencoder for Extremely Sparse Data

I am attempting to train an autoencoder on data that is extremely sparse. Each datapoint is only zeros and ones and contains ~3% 1s. Being that the data is mostly zero the autoencoder learns to ...
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Classifying sparse binary data for int value

I'm very new to data science and still trying to get the grips. The problem I'm trying to tackle is, we have a pool of footballers from a league and data objects representing a group of 11 footballers ...
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Sparse Covariance Selection

I was reading this article https://www.di.ens.fr/~aspremon/PDF/CovSelSIMAX.pdf, whose goal is to estimate the covariance matrix from a the sample covariance matrix drawn from a distribution $X$. ' ...
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Custom Loss Function for Mixing Sparse and Dense Features for a Prediction Problem

I have a largely uncorrelated feature space of about 40 dichotomous features, using which I'm trying to predict a continuous target variable. Now, some of these features are very sparse (Active less ...
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3 votes
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2k views

Converting pandas dataframe to scipy sparse arrays

Converting pandas data frame with mixed column types -- numerical, ordinal as well as categorical -- to Scipy sparse arrays is a central problem in machine learning. Now, if my pandas' data frame ...
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What are the sparse and dense vector ? I cant undestand ,can you explain to me?please.Why do we use for?

I am new to neural networks, embeddings, etc. I am struggling understanding things like sparse representation, embeddings, and especially sparse vectors. Could you explain these to me? Why do we need ...
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2 votes
1 answer
1k views

Convert Pandas Dataframe with mixed datatypes to LibSVM format

I have a pandas data frame with about Million rows and 3 columns. The columns are of 3 different datatypes. NumberOfFollowers is of a numerical datatype, UserName is of a categorical data type, ...
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Scipy Sparse vstack memory error

I have a bunch of scipy matrices (of the same #columns) loaded from disk. I want to combine them into one scipy sparse matrix. I am using scipy sparse vstack method. I am able to load the ...
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