Re: [deal.II] Segfault in EvaluatorTensorProduct::apply when AVX is enabled

2017-02-23 Thread Stephen DeWitt
Hi Martin, Thanks! I tried with the updated deal.II version and it worked like a charm. Thanks for the help and the bugfix! Best, Steve On Thursday, February 23, 2017 at 1:55:30 AM UTC-5, Martin Kronbichler wrote: > > Dear Stephen, > > The first problem you are seeing is a bug in AlignedVector:

Re: [deal.II] Segfault in EvaluatorTensorProduct::apply when AVX is enabled

2017-02-22 Thread Martin Kronbichler
Dear Stephen, The first problem you are seeing is a bug in AlignedVector::push_back. We merged a pull request last night, https://github.com/dealii/dealii/pull/3993, which should fix this issue. The problem was that we incorrectly invoked placement new with default constructor rather than the copy

Re: [deal.II] Segfault in EvaluatorTensorProduct::apply when AVX is enabled

2017-02-20 Thread Stephen DeWitt
Dear Martin, Thank you, that makes sense. If I could trouble you with one more question -- I'm having a hard time using AlignedVector, and I can't find any examples of its use online. I'd like to build the AlignedVector with a series of push backs, but I get compiler errors if I try this: dea

Re: [deal.II] Segfault in EvaluatorTensorProduct::apply when AVX is enabled

2017-02-20 Thread Martin Kronbichler
Dear Stephen, The problem is data alignment: You create an std::vector that internally arranges its data under the assumption that the start address of FEEvaluation is divisible by 32 (the length of the vectorization). If you put an FEEvaluation object on the stack, the compiler will automati

[deal.II] Segfault in EvaluatorTensorProduct::apply when AVX is enabled

2017-02-20 Thread Stephen DeWitt
Hello, I recently realized that I should be using "-march=native" flag for optimal performance of matrix-free codes. The application that I've been using works fine with just SSE2, but with AVX enabled I'm getting a segfault. Step-48 works fine, so I don't think it is an installation issue. The