DIGAMMA Function
Returns the value of the digamma function.
| Categories: | Mathematical |
| CAS |
Syntax
DIGAMMA(argument)
Required Argument
argument
specifies a numeric constant, variable, or expression.
| Restriction | Nonpositive integers are invalid. |
Details
The DIGAMMA function
returns the ratio that is given by
where 
and 
denote the Gamma function and its derivative, respectively.
For argument>0, the DIGAMMA
function is the derivative of the LGAMMA function.
and denote the Gamma function and its derivative, respectively.
For argument>0, the DIGAMMA
function is the derivative of the LGAMMA function.
Example
The following SAS statement
produces this result:
|
SAS Statement
|
Result
|
|---|---|
x=digamma(1.0); |
-0.577215665 |
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Last updated: March 16, 2017