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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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OpenModelica trivial mechanical system structurally singular

While trying to model a more complex mechanical system in OM, I got the following error: Internal error IndexReduction.pantelidesIndexReduction failed! System is structurally singular and cannot be handled because the number of unassigned equations…
ppenguin
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What causes the singular matrix error in kernel ridge regression and how to fix it?

When building a KTBoost model, I got the following error message: 1402 K.flat[::K.shape[0] + 1] += self.alphaReg 1403 self.solve_kernel=linalg.inv(K) 1404 modi =…
soniCYouth
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How to solve numerically a nonlinear ODE (a BVP) with singular points in python?

So, I have to solve numerically the following ODE y''+f(y)*(y')^2 = 0: ODE originally between [y_i,y_f] where y = y(t) and y(0) = y_i. The main problem is that the function f(y) has a (regular) singular point (couldn't post the image). Also, f(y) is…
Felipe Matus
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Rebalancing portfolio creates a Singular Matrix

I am trying to create a minimum variance portfolio based on 1 year of data. I then want to rebalance the portfolio every month recomputing thus the covariance matrix. (my dataset starts in 1992 and finishes in 2017). I did the following code which…
Grégoire Caye
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How can I estimate a latent class model with individual-specific parameters in R?

I am trying to estimate a latent class model in R based on a discrete choice experiment. Attributes in my choice set were 'COST', 'NUCL', 'REN', 'FOSS' and 'OUTAGE'. I also asked background questions which give me the variables 'MALE', 'NL', 'Y25',…
Erika De Keyser
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system is computationally singular error from linearHypothesis but the matrix has maximal rank

I'm performing a Mincer Zarnowitz to test the goodness of fit of a time series regression. The test (https://eranraviv.com/volatility-forecast-evaluation-in-r/) boils down to, first, running a regression of the observations on the fitted values, and…
Andrew
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Using observation level random effect to model overdispersion in count data and getting singular fit warning

I am fitting a glmer model with poisson error distribution and log link to test the effect of male group (treated, control) on the time spent on a specific reproductive behaviour (seconds, thus integer counts). My random factor is represented by the…
L.Loc
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'singular gradient' error when producing von Bertalanffy growth model using the nls() function

I am trying to produce a von Bertalanffy growth model in R which uses the nls() function, but getting the 'singular gradient' error The dataset 'FladenA' is in reference to the location where my sample is from, and contains 'maximum height' and…
JaneEarland
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singularity issue in mlogit model when model contains interaction

I'm using below r command on my choice model data which is perfectly working: mlmodel_BL <- mlogit(choice ~ Price + Feature + Brloy , data = mldata_BL, reflevel = "Brand4") but when I want to add interaction there, I face singularity…
Lili.Y
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Why singularity error in DCE Random Parameters model - mlogit - due to opt-out/no buy?

I'm working on a discrete choice experiment with the following characteristics: 3 alternatives which includes 1 opt-out. Each of the 2 alternatives has 3 attributes, with each attribute having 3 factor levels. Each respondent has 6 choice tasks to…
Ieben
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How to Avoid Singular Matrix using R?

I want to generate a nonsingular data matrix, and avoid the following error in R: "Error in solve.default(sigma) : system is computationally singular: reciprocal condition number = 1.3971e-16" I am using the is.singular.matrix function in R. How…
AB9
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Get singular or Plural string with regex in Java

I want to replace a variabel in a String to a singular/plural word based on a number. I've tried to use regex, but I don't know how to use a combination of regex and replaces. //INPUTS: count = 2; variable = "Some text with 2…
stijnb1234
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How do I deal with boundary (singular) fit error in my mixed effect model in R?

I'm trying to fit a mixed model to see whether or not the change in my measurements (variable "diff") is significantly different from zero (taking to account subject's individual effects). Here's my data frame: > dput(mixed) …
Nilou
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R Generalized Method Of Moments Regression Estimation With Instruments

I'm trying to train a regression model using the generalized method of moments in R. I have 3 endogenous regressors that are correlated with 6 things I know to be exogenous. My outcome variable is y I have 3 endogenous regressors: z1, z2, z1*z2 I…
DVL
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Using Devise with a singular Resource

I'm a newb with Rails and am trying to get out my first Rails 3 app with Devise. I have a situation where pretty much everything on my site is specific to a user. I'm creating a kind of private gallery that isn't public facing, so that every image…
panzhuli
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