Full_Name: Chanseok Park Version: 1.8.1 OS: linux-gnu Submission from: (NULL) (130.127.112.183)
digamma with any negative value does not give a right answer. It gives -1.797693e+308 for any negative arguments. For example, digamma(-1.1) gives -1.797693e+308. The right answer should be 10.15416 This bug can be easily fixed by using the following digamma identity. digamma(x) = digamma(1-x) - pi/tan(pi*x) ## if x is negative > digamma(-1) [1] -1.797693e+308 ## if we use the above math identity, we have the right answer ## for any negative arguments. > > x= -1.1 > digamma(1-x) - pi/tan(pi*x) ## if x is negative [1] 10.15416 > ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-devel