[Rd] dgamma error condition?

From: Ben Bolker <bolker_at_zoo.ufl.edu>
Date: Fri 04 Nov 2005 - 15:05:19 GMT

   There's an apparent inconsistency between the behavior of d(pqr)gamma and other distribution functions for "bad" parameter values. Specifically, most distributions give NaN and a warning for bad parameters (e.g. probabilities <0 or >1). In contrast, d(pqr)gamma actually gives an error and stops when shape<0. I don't see why it has to be this way -- the internal C code is set up to detect shape<0 (or scale<0) and return NaN and a warning, and none of the other distribution functions in that bit of the code have similar behavior.

   It would seem more consistent (and would be more convenient for me -- the error-instead-of-warning is making me have to jump through additional hoops) if dgamma just returned NaN and a warning.

    Any thoughts?

     Ben Bolker

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https://stat.ethz.ch/mailman/listinfo/r-devel Received on Sat Nov 05 02:19:14 2005

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