Enable caching of external evaluation results

[epitzer]

External evaluations are often very time consuming. It could be beneficial to enable caching of results to save computation time.

[epitzer]

Add new CachedExternalEvaluator with replaceable permanent cache of all evaluated solutions (r6140)

[abeham]

Hi Erik, thanks a lot for improving this! If you have some time on your hands, there are some further things that would improve the plugin. One thing would be a thread-safe version of the evaluator/client so that it works with the new parallel engine and another thing would be to enable parallelization in that a range of clients can be called so that one can run the simulations in parallel. I'd put that on our next meeting agenda if you don't mind.

[epitzer]

That is actually exactly what I had in mind too. However, this should go into another ticket. What I still like to improve here is to impose a size limit on the cache and at the same time only kick out the values that have not been reused recently.

[epitzer]

Add maximum capacity parameter and a least recently used replacement strategy to the evaluation cache (r6169)

[epitzer]

prevent additional uncached execution of base class (r6172)

[epitzer]

Prepare for parallel external evaluation (r6183)

• move cache to problem for better visibility
• configurable persistence of cache content
• proper synchronization for parallel access to cache

[epitzer]

improve synchronization of cache (r6188)

• set locks per instance instead of static
• remove failed evaluations from active set

[epitzer]

Enable export of Cache to CSV file. (r6265)

[epitzer]

fixed synchronization issue in evaluation cache and simplified event handling (r6291)

[abeham]

I reviewed the changes and have no further comments. I think the locking mechanism is reasonable and not too difficult to understand, the simplification in r6291 certainly improved readability.

[abeham]

I found some trivial issues

[abeham]

r6519

• fixed code formatting
• added some license headers
• removed unnecessary resx file