[Bonmin] does cpu time limit change the result?

[Giuseppe Aprea]

Hi,

I am solving a MINLP with algorithm B-BB. I am running the code on a
clusters so I have
problems with the queues wall time. That forces me to to introduce
max_cpu_time in the
bonmin option file. Since I have no idea of how much CPU time I will
need I am trying each
time increasing the value of the option.

Curiously I am experiencing two opposite behaviours

if  max_cpu_time ~< 600 I get infeasibility

if max_cpu_time ~> 600 the computation last for hours but looking at
the output it seems that
there is no more infeasibility.


I wonder if

- max_cpu_time can make Ipopt gives infeasibility
- max_cpu_time only stops a single Ipopt iteration so
if each iteration had duration less than max_cpu_time bonmin
would never stop

if the answer to both previous question is yes:

is there a method to retrieve the last good solution?
is there an option, other than max_cpu_time, to stop the process and
which does not give infeasibility?

cheers,

giuseppe