logmdigamma {statmod} | R Documentation |
Log Minus Digamma Function
Description
The difference between the log
and digamma
functions.
Usage
logmdigamma(x)
Arguments
x |
numeric vector or array of positive values. Negative or zero values will return |
Details
digamma(x)
is asymptotically equivalent to log(x)
. logmdigamma(x)
computes log(x) - digamma(x)
without subtractive cancellation for large x
.
Author(s)
Gordon Smyth
References
Abramowitz, M., and Stegun, I. A. (1970). Handbook of mathematical functions. Dover, New York.
See Also
Examples
log(10^15) - digamma(10^15) # returns 0
logmdigamma(10^15) # returns value correct to 15 figures
[Package statmod version 1.5.0 Index]