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 constructor.
Regarding your second approach: I am not sure what prevents this from working. I have tried a similar approach and it does work in principle, at least with the latest developer version. Apart from the fact that you actually access invalid memory since you only call reserve(1) and never extend the size to one. Could you please try with the updated deal.II version and report back in case you have further problems? Thanks! Best, Martin On 02/20/2017 11:01 PM, Stephen DeWitt wrote: > 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: > > | > dealii::AlignedVector<typeScalar>scalar_vars; > typeScalar var1(data,0); > scalar_vars.push_back(var1); > | > > tellling me that: > /Applications/deal.II.app/Contents/Resources/include/deal.II/base/aligned_vector.h:640:21: > error: no matching constructor for initialization of > 'dealii::FEEvaluation<2, 1, 2, 1, double>' > new (_end_data) T; > > and: > /Applications/deal.II.app/Contents/Resources/include/deal.II/base/aligned_vector.h:641:16: > error: object of type 'dealii::FEEvaluation<2, 1, 2, 1, double>' > cannot be assigned because its copy assignment operator is implicitly > deleted > *_end_data++ = in_data; > > I also tried: > > | > dealii::AlignedVector<typeScalar>scalar_vars; > scalar_vars1.reserve(1); > typeScalar var1(data,0); > scalar_vars1[0]=var1; > | > > but still got the "error: object of type 'dealii::FEEvaluation<2, 1, > 2, 1, double>' cannot be assigned because its copy assignment operator > is implicitly deleted" error. > > How should I be making my AlignedVector? > > Thanks, > Steve > > > > On Monday, February 20, 2017 at 3:23:09 PM UTC-5, Martin Kronbichler > wrote: > > Dear Stephen, > > The problem is data alignment: You create an > std::vector<FEEvaluation> 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 automatically > do it right. However, inside an std::vector it would be up to the > std::vector to ensure this, but on usual x86-64 machines it only > aligns to 16 byte boundaries. This is also why SSE2 works because > it only needs 16-byte alignment. > > The solution is to use AlignedVector<typeScalar> scalar_vars > instead of std::vector. The alternative is to wait until the pull > request 3980 (https://github.com/dealii/dealii/pull/3980 > <https://github.com/dealii/dealii/pull/3980>) gets merged, grab > the newest developer version because with that we will start using > an external scratch data array that always has the correct alignment. > > Best, > Martin > > > On 20.02.2017 20:50, Stephen DeWitt wrote: >> 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 function where it occurs is similar to the "local_apply" >> function in step 48: >> | >> template<intdim> >> voidgetRHS(constMatrixFree<dim,double>&data, >> >> std::vector<dealii::parallel::distributed::Vector<double>*>&dst, >> >> conststd::vector<dealii::parallel::distributed::Vector<double>*>&src, >> conststd::pair<unsignedint,unsignedint>&cell_range)const{ >> >> //initialize FEEvaulation objects >> std::vector<typeScalar>scalar_vars; >> >> for(unsignedinti=0;i<num_var;i++){ >> typeScalar var(data,i); >> scalar_vars.push_back(var); >> } >> >> //loop over cells >> >> for(unsignedintcell=cell_range.first;cell<cell_range.second;++cell){ >> >> // Initialize, read DOFs, and set evaulation flags >> scalar_vars[varInfoListRHS[i].index].reinit(cell); >> >> >> scalar_vars[varInfoListRHS[i].index].read_dof_values_plain(*src[varInfoListRHS[i].global_var_index]); >> >> >> scalar_vars[varInfoListRHS[i].index].evaluate(need_value[i],need_gradient[i],need_hessian[i]); >> >> // <--- segfault happens here! >> >> } >> >> unsignedintnum_q_points; >> num_q_points =scalar_vars[0].n_q_points; >> >> //loop over quadrature points >> for(unsignedintq=0;q<num_q_points;++q){ >> (etc.) >> | >> >> >> The segfault happens during the "evaluate" call. GDB tells me >> that it happens on line 5478 of >> /include/deal.II/matrix_free/fe_evaluation.h, in >> EvaluatorTensorProduct::apply: >> | >> xp[i]=in[stride*i]-in[stride*(mm-1-i)]; >> | >> >> Using the debugger to step through EvaluatorTensorProduct::apply, >> nothing seems obviously wrong. As expected, all of the vectorized >> arrays are four doubles long. The line above evaluates to >> xp[0]=in[0]-in[1]. >> >> Has anyone else had this issue? Does anyone have ideas what the >> problem could be, or what I should be looking for? >> >> Thanks! >> Steve >> >> System: Cluster running CentOS 7, with Intel Xeon E5-2670 >> processors, GCC v5.4.0 >> >> >> >> >> -- >> The deal.II project is located at http://www.dealii.org/ >> For mailing list/forum options, see >> https://groups.google.com/d/forum/dealii?hl=en >> <https://groups.google.com/d/forum/dealii?hl=en> >> --- >> You received this message because you are subscribed to the >> Google Groups "deal.II User Group" group. >> To unsubscribe from this group and stop receiving emails from it, >> send an email to dealii+un...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. > > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en > --- > You received this message because you are subscribed to the Google > Groups "deal.II User Group" group. > To unsubscribe from this group and stop receiving emails from it, send > an email to dealii+unsubscr...@googlegroups.com > <mailto:dealii+unsubscr...@googlegroups.com>. > For more options, visit https://groups.google.com/d/optout. -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. 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