Multi-threaded solver warning 1

[Kristene]

Hi,

I came across a "warning" when using "Multi-threaded solver". SAP2000 reports structure is ill conditioned/unstable and suggests using "Standard solver". See the attached screenshot for warning message. When I analysed the same model using Advanced/Standard solver not even a single warnings. I was unable to make sense out of it, please let me know if you found something.

Thanks,

 

[JoshPlumSE]

I have no experience with SAP2000 and this type of error. However, based on my work developing similar software (RISA) I can guess at the intent of this error message.

Whenever a software program introduces a new or advanced solver, it is likely to encounter "issues" with the solver. If we've been using the same software in our program for 20+ years, then we have good error messages that trigger anytime anything unusual pops up. We've got tolerances and special routines built into the solver to handle other "issues" internally without annoying the user.

But, the newer solvers don't have those multiple years worth of de-bugging, so they are likely to generate more error messages. Sometimes those error messages are going to be less explanatory than you would get with the regular solver. When this happens, the software will often point you back to the older (and slower) solvers because we know that they will either be able to handle the issue or will give a better error message about what exactly the issue is.

 

[GregLocock]

There's a specific issue with multi threaded solvers vs single threaded. The job has to be partitioned between the different threads, and it is not unusual for a model to be too elaborately interconnected for the partitioning to work.

Cheers

Greg Locock


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