[Ipopt] Ipopt halts on log(0.38)

[Giacomo Nannicini]

Hi all,
I am experiencing a strange behavior of Ipopt.
I have a model that contains logarithms of nonnegative numbers.
Everything runs fine on my machine, where I compiled from source and
use ma27 as linear solver.
However on a different machine I use the Ipopt binaries downloaded
from the AMPL website, that use mumps. On this machine, running the
model gives an error:

Error evaluating constraint 1: can't evaluate log(0.388348).

To get this message I have to run with halt_on_ampl_error yes,
otherwise Ipopt simply exists with Invalid number in NLP function or
derivative detected.
I am not even sure this is an error of Ipopt or ASL, but it's hard for
me to figure out where the error is coming from.

Attached is a small and compressed .nl file that exhibits this behavior.

Any ideas? I can't see why log(0.38) would be a complicating
expression, what am I missing?

Thanks

Giacomo
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