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Questions tagged [singular]

Singularity is a mathematical term indicating an undefined point on a set (function). Singularity arises in many mathematical optimization problems with many variables.

An example of singularity is the derivative of the absolute value function |x| at x = 0.

Singularity arises in many ill-posed problems

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How to count the number of plurals and singulars given a corpus in Python

I hope you can help me with a task. I need to count the number of plurals and singulars in a corpus. I have a corpus whose lines have the following structure: ['4', 'lanzas', 'lanza', 'NCFP000'] the first position [0] counts for a number (4), the…
sara montenegro abad
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Getting singular form of homograph words in Laravel

When using str_singular() function in Laravel to get a singular form of word 'leaves' it returning 'leaf'. However I need to get 'leave' word, like in 'leave of absence'.
Mhmoud
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Cannot estimate difference-in-differences RE model (system is exactly singular error)

I'm trying to estimate a DiD model using panel data methods (pooling, FE and RE). The model is used to determine whether a cartel presence (dummy variable E1 in regression - 1 for the cartel period and 0 otherwise) affects the consumer price of fish…
DenizKutlu
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Eigen: understand preconditioner concept

I try to write a custom preconditioner, but do not understand the concept of Eigen's preconditioner so far. My current state looks like this, but there is something obvious wrong... class NullSpaceProjector: public Eigen::IdentityPreconditioner { …
Lo L
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Invert singular matrices in R

I am trying to grasp the basic concept of invertible and non-invertible matrices. I created a random non-singular square matrix S <- matrix(rnorm(100, 0, 1), ncol = 10, nrow = 10) I know that this matrix is positive definite (thus invertible)…
Jespar
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LinAlgError: Singular matrix in using statsmodel

I have a regression problem at hand and know that the error is caused by multicollinearity of input variables, but I am having a hard time to find how to identify those extra variables and remove them from the regression model to make it work. Here…
Kexin Xu
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Singular matrix errors in quantile regressions

I'm trying to run some quantile regressions in R. The response variable is continuous. The predictor variables are categorical, taking values [0, 1, 2, 3, 4]. Every time I try to do any analysis, I get error messages (examples of commands and errors…
AmSr
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What is the threshold for "tf.matrix_inverse()" as singular matrix?

I am using tf.matrix_inverse() to compute the inverse of matrix. Sometimes, the matrix is very close to singular but not singular. I wonder in Tensorflow what's the threshold (or how close determinant of matrix to 0) for tf.matrix_inverse() to…
Ruofan Kong
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"system is computationally singular" brnn package

I am using brnn package to fit a regularized neural network to my data. In some cases, I get an error: Error in solve.default(2 * beta * H + ii(2 * alpha, npar)) : system is computationally singular: reciprocal condition number =…
JerryTheForester
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SQLite singular/plural search

I'm building an Android app for a college project. It searches an SQLite database for recipes according to ingredients that the user specifies. I'm still at the beginning, and I've run into this problem. I'm storing ingredients as singular in the…
user3501779
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Reproducing Singular Value Decompition in R

I have an example word by document matrix (from Landauer and Dumais, 1997): wxd <- matrix(c(1,1,1,0,0,0,0,0,0,0,0,0, 0,0,1,1,1,1,1,0,1,0,0,0, 0,1,0,1,1,0,0,1,0,0,0,0, 1,0,0,0,2,0,0,1,0,0,0,0, …
snarble
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JavaFX - How to use multiple same type of event handlers on a single node

I've got 2 ListViews (A and B) of the same base type. What I need to implement is: - user drags items from A, drops them into B - user drags items from B, drops them into B(rearrangement). The changes has to be saved in an sqlite table. 2 different…
Laszlo Moricz
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Align 2 sets of 3D points in Unity by using Singular Value Decomposition method (SVD)

I wanted to translate a set of reference points on contour to a set of corresponding target points. There are total 8 points on each contour. In order to calculate the rotation & translation vector, I was using Math.Net Numerics library to perform…
mcmc
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Java - Matrix is singular

I have this code: OLSMultipleLinearRegression regression = new OLSMultipleLinearRegression(); double[] consumptions = new double[vec.size()]; double[][] x = new double[(int) (trainPart * vec.size())][3]; while (it_vec.hasNext() ) { …
Daniel Herbrych
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How to solve singular matrices?

I need to solve more than thousand matrices in a list. However, I get the error Lapack routine dgesv: system is exactly singular. My problem is that my input data are non singular matrices, but following the calculations I need to do on the matrices…
N.Varela
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