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I am attempting to reproduce results of this paper in R, but I am stuck on two parts.

  1. plotting the normalized lower incomplete gamma functions enter image description here

  2. calculating the loss function

enter image description here

This problem would be solved if there existed a function in R that computed the normalized lower incomplete gamma function. So my question is, how can I calculated the normalized lower incomplete gamma function

Alex
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  • "but I am stuck ..." How so? What have you tried? In any event, without reading whatever paper you are referring to, it is hard to know what all of this notation actually means. This question lacks context. – John Coleman Mar 20 '18 at 10:44
  • Thanks @JohnColeman . I updated my question to one specific function. – Alex Mar 20 '18 at 12:07
  • The question is now sufficiently focused and already has a good, accepted, answer. I thus vote to reopen it. – John Coleman Mar 20 '18 at 16:50

1 Answers1

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pgamma is the normalized lower incomplete gamma function, see ?pgamma:

pgamma is closely related to the incomplete gamma function. As defined by Abramowitz and Stegun 6.5.1 (and by ‘Numerical Recipes’) this is

P(a,x) = 1/Gamma(a) integral_0^x t^(a-1) exp(-t) dt

Julius Vainora
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