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Questions tagged [gamma]

Gamma questions pertain to non-linear responses in the display chain. The application, adjustment or compensation for gamma, as well as the consequences of doing or not doing so are common subjects.

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(DirectX9) Gamma correction applied implicitely

UPDATE: Thank you all very much for your answers. As Jesse Hall suggested, it looks like it is a driver (or hardware) problem. I tried the same app on other configurations and it worked as expected. I tested the app on other computers which share…
Ozirus
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(DirectX9) sRGB conversion after blending

I recently came across this blog post Yet another post about gamma correction which taught me the availability of the D3DPMISCCAPS_POSTBLENDSRGBCONVERT capability flag. This should allow for proper sRGB conversion after blending on DirectX9. What I…
Ozirus
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In R, what is the default link function using the glm function with the gamma family

I have implemented a model using the glm() function and specifiy the family distribution as gamma: glmer(FirstSteeringTime ~ error_rate + (1 + error_rate | pNum), family = Gamma, data = modellingdata) I know that you can apply link functions such…
codegoblin1996
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Left-Truncated Gamma Fitting

I am trying to fit a left-truncated gamma distribution in R. I have large claims above $25,000. Claims below $25,000 are unknown. I am trying to fit the gamma parameters through the MLE procedure in R. Could anyone suggest code for this? My current…
ryangold96
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Gamma random numbers, MATLAB and Python

I have this line of code in a MATLAB program: x(:,i) = gamrnd(a(i),1,dim,1) I was wondering in what way I could write this same line in Python. I think the equivalent statement is: gamma.rvs(a, size=1000) However, this keeps giving me an Index…
A.Torres
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Metal: How to attach image to shader without color/gamma conversion?

Is it possible to send an image to a metal shader (from scenekit) without any color/gamma correction? I have a data texture where each channel corresponds to specific values that I want to be able to test against. It's a world map with the green…
deanhet
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Gamma Distribution in R (qgamma)

This may be a very stupid question but Does anyone know why i am not getting the second bit equals to the mean (100)? #beta=4, alpha=5, mean=20 qgamma(0.5, 5, 1/4) # 18.68364 #beta=2500, alpha=0.04, mean=100 qgamma(0.5,0.04,1/2500) # 0.00004320412
syys
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Shape parameter of gamma full conditional tau is too small, WinBUGS

I'm trying to code a reserving model and I'm encountering some problems: When I press "load inits", I get the message this chain contains unitialized variables although I've initialized all my variables. Ignoring the first problem and pressing…
Kostas Passas
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How to calculate the mean of a fitted gamma distribution?

I used scipy.stats.gamma.fit(data) to fit a gamma distribution to my data. I want to know what the mean of the resulting distribution is. How do I find the mean of the fitted gamma distribution?
Ellen
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How to convert scroll bar position to gamma correction?

I want to build a constant array(1..200) of single numbers to make a 'lookup table' to convert the position of the scrollbar which has values 1 - 200 to a value to use for applying gamma correction to an image. The first array value would have a…
BadDog
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fitting location parameter in the gamma distribution with scipy

Would somebody be able to explain to me how to use the location parameter with the gamma.fit function in Scipy? It seems to me that a location parameter (μ) changes the support of the distribution from x ≥ 0 to y = ( x - μ ) ≥ 0. If μ is positive…
emac
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Why do I have to use a gamma of 2.2 when using a JPEG picture?

During the rendering process, the texture file have a gamma of 2.2. But the plain color do not need this gamma correction, especially if the RGB values are from a spectral caracterisation. So, Why have I to use a gamma of 2.2 into my texture files…
Tofuw
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R: Prediction using glm() gamma family

I am using glm() function in R with link= log to fit my model. I read on various websites that fitted() returns the value which we can compare with the original data as compared to the predict(). I am facing some problem while fitting the…
Nikita
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How to plot a Q-Q plot of data versus a custom theoretical function

I'd like to make a visual assessment of whether my data conform to a particular distribution function. To do this, I am using R to generate a quantile-quantile (Q-Q) plot. The distribution function is very specific and is not featured in the…
Mirella
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Fitting either Guassian or Gamma distribution to data in Python

I have some measured data which can be either a well established gaussian or something that seems to be a gamma distribution, I currently have the following code (snippet) which performs quite well for data that is nicely gaussian: def…
Bas Jansen
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