Evaluation performance for large numbers

[marcellustavares]

Hey Udo, first of all thanks for the awesome library!

I'm using the EvalEx library for the Liferay portal project but we've found something that impacts the performance of some operations.

For example expression such as SQRT(9123744984893^993837) takes a lot of time to evaluate and the eval() method hangs for a while.

We can solve this at our side, but I was wondering if that's something you would like to include in your library. Something like a timed out condition for evaluations. I can send you a pull request if you think so.

Let me know what you think.

Best Regards @uklimaschewski,

[uklimaschewski]

Thank you, I marked this as an enhancement. If you send a pull request, I can have a look at it.

[uklimaschewski]

It's been a while, but today I was playing around with some possibilities for a timeout. It seems that the problems are in the BigDecimal class, which can be very slow on very large numbers. Do you have a working solution and how does it work? The only solution that I came up with, was using separate threads, but this is not nice and the Expression class is IMHO not the right place to handle this.

[marcellustavares]

hey @uklimaschewski, sorry for the delay. Yeah, it's not so simple unfortunately. My workaround was to limit the numeric range of some operations to double.

It was something we could afford on our side but it's definitely not the solution for EvalEx.

Thanks a lot for all the help!