Anything related to the mathematical gamma function, also known as generalized factorial function.
Anything related to the mathematical gamma function, also known as generalized factorial function.
See Wikipedia page on gamma function.
Questions tagged [gamma-function]
72 questions
0
votes
1 answer
Roots of digamma function in R
I am working on a maximum likelihood estimator, and one of the parameters is estimated using the digamma function. I'm trying to use uniroot to solve the equation but am unable to do so. Here's my code:
dig = function(alpha){
digamma(2 +…
sqlck
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0
votes
0 answers
Division of two incomplete gamma function
I am working on an equation that needed to divide two incomplete gamma functions. They are just different by the first term as they are IG(a,b) and IG(2a,b). Is there any closed form or simple approximation for the division?
TPArrow
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0
votes
1 answer
Decode a gamma encoded image
I am working on a project, where the user can specify a gamma function on a image, for example:
y=(pow(10,(1023*x-681)/444)-.0408)/(1-.0408))
The image is then encoded with this gamma curve, and then my code must be able to return this image back…
Malu05
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0
votes
1 answer
Estimate pi with Gamma function in Python Monte Carlo method
I'm trying to write a code in python using the Monte Carlo method to estimate pi (where pi = gamma(1/2)**2). I should write a code saying that sqrt(pi) is the area of a square enclosing the function gamma(x=1/2) times the total number of random…
JadeChee
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0
votes
2 answers
Gamma function approximation
I'm trying to write a three-parameter method that approximates the gamma function over a certain interval. The approximation should be a right-endpoint Riemann sum.
The gamma function is given by:
GAMMA(s) =
inf
INT x^(s-1) * exp(-x) dx
0
The…
Ice101781
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- 10
0
votes
1 answer
Fast incomplete gamma function
What is a fast way to calculate the incomplete gamma function, or at least a "good" approximation of it, in C++?
Background
What I ultimately need to calculate
Given a number of Bernoulli trails N, with probability p of success, I'm ultimately…
Museful
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-1
votes
1 answer
scipy gamma distribution doesn't match formula on wikipedia
According to Wikipedia the expected value of a Gamma distribution is k * theta. However, when I plug that into the CDF for the gamma distribution I don't get 0.5 as expected.
k = 1.5
theta = 2.1
expected_value = k *…
Aaron
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-1
votes
1 answer
Is there a function in R which finds z if I know y in gamma(z)=y
I am looking to know if there is any function in R which finds z if I know y and
gamma(z)=y
Uniroot might be useful but not sure how I can use this.
Thanks
Mohsen Sichani
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-1
votes
1 answer
Database structure is from newer Gammu version
i get error when run gammu-smsd
Log filename is "/var/log/gammu-smsd"
gammu-smsd[11271]: Database structure is from newer Gammu version
gammu-smsd[11271]: Initialisation failed, stopping Gammu smsd: Unknown error. (UNKNOWN[27])
Failed to run SMSD:…
kputri
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votes
1 answer
MATLAB strange error Gamma function numerical integration
i try to run the following in order to integrate numerically:
nu = 8;
psi=-0.2;
lambda = 1;
git = @(u) tpdf((0 - lambda * skewtdis_inverse(u, nu, psi)), nu);
g(t,i) = integral(git,1e-10,1-1e-10,'AbsTol',1e-16);
where tpdf is a matlab function and…
InfiniteVariance
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- 8
-2
votes
2 answers
Error:identifier tgamma is undefined in c++ although is included
Im trying to use tgamma function in c++ 10.It's running on a 32-bit machine. I've included , but still getting the error "identifier tgamma is undefined ". what could be the reason?
NavidAmin
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-5
votes
1 answer
Exponential integral and gamma function
In order to solve this problem, without iteration:
Recursion: Sum of series of n terms
calculating for a given n: 1 + 2*3 + 3*4*5 + 4*5*6*7 + ... +
n*(n+1)...(2n-1)
with this mathematical…
guillaume girod-vitouchkina
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