[Ipopt] Ipopt halts on log(0.38)

Giacomo Nannicini giacomo.n at gmail.com
Thu Aug 10 11:04:53 EDT 2017

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?


-------------- next part --------------
A non-text attachment was scrubbed...
Name: logarithm_error.tar.gz
Type: application/x-gzip
Size: 1351 bytes
Desc: not available
URL: <http://list.coin-or.org/pipermail/ipopt/attachments/20170810/30a4a9ec/attachment.bin>

More information about the Ipopt mailing list