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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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Equipotential lines / contour plot with singularities

I'm having trouble to create a plot with equipotential lines in gnuplot. Here is what I got so far: f(x,y) = atan(y/(x+d)) d = 1.0 set view map set isosamples 127, 127 unset surface set contour base set cntrparam levels discrete pi/4.0 set xrange…
nox
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Assigning boost::iterator_range to singular range

I'm using Boost.Range to pass around some data and a container class for this data. The data is loaded in a different thread and may in some cases not be ready yet. In this case the container is initialized with the default iterator_range, hence…
larsmoa
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Hausman test has singularity in R

My data is stored in a dataframe called 'Gap3',and the structure is like below: > summary(Gap3) region time rC2R g Beijing : 19 1995 : 31 Min. :0.000 Min. : 3.80 Tianjin : 19 …
Jim
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error in optim while using method="L-BFGS-B ", L-BFGS-B needs finite values of fn

I am using 'optim' with method L-BFGS-B for estimating the parameters of a tri-variate lognormal distribution using a tri-variate data. Following are the commands I have used. #Definition of logliklihood logl <- function (theta,…
zahra
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Matlab singular matrix solver

If matrices AX=B, and A = 3x3, B=3x1, and A is singular, and B has non zero numbers. Solve for X Is this possible to solve for? How can you solve for X in MATLAB, is it possible to solve this by hand? I know that is A is singular because det(A) = 0…
user4999605
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Prove Theorem with Groebner Basis

I'm trying to prove some theorems using Groebner Basis (as described in Cox, Little and O'Shea Link ) The mentioned book gives as an excercise to prove Pappus theorem using the given methodology, but I really can't make it work. I've tried usign…
Francisco Martínez
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Ordinary Kriging in 2D and 3D: Are duplicate points an issue?

I wish to krige in 2 dimensional and 3 dimensional domain (separately). I have many points, that have been replicated below. NOTE: The attribute I wish to krige on is Y. These are intentionally negative since they are exponents values. The…
makansij
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Mixing Plural AND Singular naming

here's the quick version of the situation: We are developing some C# App and the team decided this Naming convention: We have for example an entity called User which is stored in the DB, we have the old master/slave pages to manage the User…
Luj Reyes
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Rails controller method going to plural form

I'm new to rails! Ok, I am trying to set up a user signup form. It is mapped as a singular resource in the routes map.resource :user And trying to create the user through the console works fine. the controller code for user's signup is as follows: …
Jty.tan
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R nls gaussian fit "singular gradient matrix at initial parameter estimates"

I tried to fit my data with a gaussian curve using nls. Because that didn't work, i tried to make an easy example to see what goes wrong: >x=seq(-4,4,0.1) >y=2*dnorm(x-0.4,2)+runif( length(x) , min = -0.01, max = 0.01) >df=data.frame(x,y) >m <-…
user1402050
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Debugging in matlab

I want to know which line caused Matrix Close to Singular Warning in matlab. How can I do it? Right now I have lots of places where I try to invert the matrix. I want to know at which particular place it was raised.
user34790
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rails singularize to a / an

Is there a method that works similar to singularize to prepend "a" or "an according to the word? like f(apple) # => an apple f(carpet) #=> a carpet
Nick Ginanto
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Mysql select on word (plural, singular)

In my Mysql DB I have a list of terms like (With First letters Capital and most of the time plurals) Hairdressers Restaurants Beauty Salons Fournitures For Restaurants On my website I have a searchbar where the user can search for those word (my…
Johny19
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Is there an algorithm for finding every isolated singular point on an algebraic variety, or a programming language that implements this?

(note: this question was closed on math stack exchange before it was answered, so I'm asking it here) Suppose one wishes to test if a given surface f(x,y,z,w) = 0 in projective 3 space has singular points (i.e. df/dx = df/dy = df/dz = 0), and one…
drfpslegend
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What causes the 'Duplicate class' error in Singular setup for Flutter apps, and how to fix it?

Implementing Singular in Flutter application and getting sdk setup error. Execution failed for task ':app:checkDebugDuplicateClasses'. > A failure occurred while executing com.android.build.gradle.internal.tasks.CheckDuplicatesRunnable >…
Vatsal Gadhiya
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