recursive algorithm makes Rhino crash

Replies to This Discussion

Permalink Reply by Danny Boyes on March 31, 2014 at 3:33am

Same happens to me (64 bit, 8GB of RAM)

Permalink Reply by panhao on March 31, 2014 at 3:49am

My PC :XEON E3 1230v2  64bit 8GB

Rhino 5 and Grasshopper 090072

Permalink Reply by David Rutten on March 31, 2014 at 4:31am

Recursion -when naively implemented- requires more and more memory space to keep the function call stack. Function stack space is very limited and quickly runs out. When it does, you crash. 

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David Rutten

david@mcneel.com

Permalink Reply by panhao on March 31, 2014 at 11:53am

Can I set the RAM limitation manually to solve that problem?Is there a setting about RAM in Grasshopper090072?

Permalink Reply by David Rutten on March 31, 2014 at 3:05pm

It's not about how much memory you have left on RAM, it's about how much memory is allotted for the call stack, which is not something you can control. I don't know for sure but it's probably hard-coded.

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David Rutten

david@mcneel.com

Permalink Reply by Mateusz Zwierzycki on March 31, 2014 at 3:44pm

Would freezing the thread for some time help ?

Permalink Reply by David Rutten on March 31, 2014 at 3:51pm

No. It will delay the inevitable, but nothing else.

Seriously, there's no decent solution without redesigning the algorithm. Using recursion by having a function call itself over and over will crash the computer sooner or later. This is why there are often iterative and tail-recursive alternatives to naive-recursive functions.

The recursion depth should be in the hundreds of nested layers though, if you're running into this limitation, are you sure your algorithm is not stuck? It seems like you'd rarely need to go that deep.

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David Rutten

david@mcneel.com

Permalink Reply by panhao on April 13, 2014 at 11:02pm

Using OOP instead finally solve my problem.Maybe recursive is not suitable for large inputs.

Permalink Reply by Mostapha Sadeghipour Roudsari on March 31, 2014 at 9:00am

You can still fake the recursive process! Copy the same function with a different name and call the new function (which is actually the same function) at the end of your function. It will let the system to reset the memory each time for the function so it won't crash.