Package: pari
Version: 2.8.0

The function ispower will give a domain error when given a "large" negative argument.  This is a regression from 2.5.5.


? ispower(-167^10)
  ***   at top-level: ispower(-167^10)
  ***                 ^----------------
  *** ispower: domain error in mplog: argument <= 0
  ***   Break loop: type 'break' to go back to GP prompt

Works in Pari 2.5.5, fails after commit 3bb8081166c9ac6915977323a4751669ae6c9ed0 from July 2013.  Still fails in today's git master.

-101^10   works
-103^10   fails

-7079^5   works
-8093^5   fails

The expectation is that these return an answer (5 in these examples), and not give a domain error in a function ispower is internally calling.  I'm sorry I cannot provide a patch.

Tested on x86 Fedora and Darwin.