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# Compute the Logarithmic Derivative of the gamma Function in R Programming – digamma() Function

• Last Updated : 12 Jun, 2020

`digamma()` function in R Language is used to calculate the logarithmic derivative of the gamma value calculated using the gamma function.
digamma Function is basically,

`digamma(x) = d(ln(factorial(n-1)))/dx`

Syntax: digamma(x)

Parameters:
x: Numeric vector

Example 1:

 `# R program to find logarithmic derivative ``# of the gamma value`` ` `# Calling the digamma() Function``digamma(``2``)``digamma(``4``)``digamma(``5.2``)`

Output:

```[1] 0.4227843
[1] 1.256118
[1] 1.549434
```

Example 2:

 `# R program to find logarithmic derivative ``# of the gamma value`` ` `# Creating a vector``x <``-` `c(``2.3``, ``3``, ``1.2``)`` ` `# Calling the digamma() Function``digamma(x)`` ` `# Calling digamma() function``# on negative values``digamma(``-``2.3``)``digamma(``-``2``)`

Output:

```[1]  0.6000399  0.9227843 -0.2890399
[1] 3.317323
[1] NaN
Warning message:
In digamma(-2) : NaNs produced
```
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