just one other thing about the AIC issue: there is a line in glm.fit which is the following: aic = aic(y, n, mu, weights, dev) + 2 * rank but I couldn't find the function aic so I couldn't investigate further. It looks suspicious though because it seems to me like it should be aic = -2*likelihood + 2 * rank if anyone could help me find the aic function it's appreciated. [[alternative HTML version deleted]]
On 2012-05-31 07:52, Mark Leeds wrote:> just one other thing about the AIC issue: > > there is a line in glm.fit which is the following: > > aic = aic(y, n, mu, weights, dev) + 2 * rank > > but I couldn't find the function aic so I couldn't investigate further. It > looks suspicious though because it seems to me like > it should be > > aic = -2*likelihood + 2 * rank > > if anyone could help me find the aic function it's appreciated.Have a look at ?family to see that the family object used in glm.fit() is a list most of whose elements are functions. The code in glm.fit() has a few lines extracting those functions, one of which is aic(). The 'gf <- Gamma()' example on the help page for family is informative as is the annotated code for glm.fit in the sources. Peter Ehlers --
On 01/06/12 02:52, Mark Leeds wrote:> just one other thing about the AIC issue: > > there is a line in glm.fit which is the following: > > aic = aic(y, n, mu, weights, dev) + 2 * rank > > but I couldn't find the function aic so I couldn't investigate further. It > looks suspicious though because it seems to me like > it should be > > aic = -2*likelihood + 2 * rank > > if anyone could help me find the aic function it's appreciated.Dear Mark, The aic() function depends on the family that you are using. E.g.: binomial()$aic gaussian()$aic cheers, Rolf