From: Martin Kronbichler Date: Sat, 20 Apr 2024 05:56:20 +0000 (+0200) Subject: FEPointEvaluation: Allow evaluating more points together X-Git-Tag: v9.6.0-rc1~347^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F16910%2Fhead;p=dealii.git FEPointEvaluation: Allow evaluating more points together --- diff --git a/include/deal.II/matrix_free/fe_point_evaluation.h b/include/deal.II/matrix_free/fe_point_evaluation.h index d66926e889..9ee92802d6 100644 --- a/include/deal.II/matrix_free/fe_point_evaluation.h +++ b/include/deal.II/matrix_free/fe_point_evaluation.h @@ -1842,8 +1842,6 @@ FEPointEvaluationBase:: , current_face_number(other.current_face_number) , fast_path(other.fast_path) , is_reinitialized(false) - , shapes(other.shapes) - , shapes_faces(other.shapes_faces) , is_interior(other.is_interior) { connection_is_reinitialized = mapping_info->connect_is_reinitialized( @@ -1879,8 +1877,6 @@ FEPointEvaluationBase:: , current_face_number(other.current_face_number) , fast_path(other.fast_path) , is_reinitialized(false) - , shapes(other.shapes) - , shapes_faces(other.shapes_faces) , is_interior(other.is_interior) { connection_is_reinitialized = mapping_info->connect_is_reinitialized( @@ -2064,13 +2060,16 @@ FEPointEvaluationBase::do_reinit() if (!is_linear && fast_path) { const std::size_t n_shapes = poly.size(); + if (is_face) + shapes_faces.resize_fast(n_q_batches * n_shapes); + else + shapes.resize_fast(n_q_batches * n_shapes); for (unsigned int qb = 0; qb < n_q_batches; ++qb) if (is_face) { if (dim > 1) { - shapes_faces.resize_fast(n_q_batches * n_shapes); internal::compute_values_of_array( shapes_faces.data() + qb * n_shapes, poly, @@ -2080,12 +2079,31 @@ FEPointEvaluationBase::do_reinit() } else { - shapes.resize_fast(n_q_batches * n_shapes); - internal::compute_values_of_array( - shapes.data() + qb * n_shapes, - poly, - unit_point_ptr[qb], - update_flags & UpdateFlags::update_gradients ? 1 : 0); + if (update_flags & UpdateFlags::update_gradients) + { + internal::compute_values_of_array(shapes.data() + qb * n_shapes, + poly, + unit_point_ptr[qb], + 1); + } + else if (qb + 1 < n_q_batches) + { + // Use function with reduced overhead to compute for two + // points at once + internal::compute_values_of_array_in_pairs( + shapes.data() + qb * n_shapes, + poly, + unit_point_ptr[qb], + unit_point_ptr[qb + 1]); + ++qb; + } + else + { + internal::compute_values_of_array(shapes.data() + qb * n_shapes, + poly, + unit_point_ptr[qb], + 0); + } } } diff --git a/include/deal.II/matrix_free/tensor_product_point_kernels.h b/include/deal.II/matrix_free/tensor_product_point_kernels.h index 0fed110392..9b7bb7a2a9 100644 --- a/include/deal.II/matrix_free/tensor_product_point_kernels.h +++ b/include/deal.II/matrix_free/tensor_product_point_kernels.h @@ -52,8 +52,8 @@ namespace internal /** - * Computes the values and derivatives of the 1d polynomials @p poly at the - * specified point @p p and stores it in @p shapes. + * Compute the values and derivatives of the 1d polynomials @p poly at the + * specified point @p p and store them in @p shapes. */ template inline void @@ -90,6 +90,43 @@ namespace internal + /** + * Evaluate the 1d polynomials @p poly at the two specified points @p p0 and + * @p p1 and store them in @p shapes. This function can be used as a more + * efficient alternative to the compute_values_of_array() function, because + * of reduced overhead when querying the polynomials (which usually have + * loop bounds that are not known at compile time). + */ + template + inline void + compute_values_of_array_in_pairs( + dealii::ndarray *shapes, + const std::vector> &poly, + const Point &p0, + const Point &p1) + { + // Use 'int' variable here to let the compiler apply additional + // optimizations, in particular regarding multiplications and additions in + // loop increments that are known not to overflow/wrap around (as is the + // case for unsigned int). + const int n_shapes = poly.size(); + + std::array point, result; + for (unsigned int d = 0; d < dim; ++d) + point[d] = p0[d]; + for (unsigned int d = 0; d < dim; ++d) + point[dim + d] = p1[d]; + for (int i = 0; i < n_shapes; ++i) + { + poly[i].values_of_array(point, 0, &result); + for (unsigned int j = 0; j < 2; ++j) + for (unsigned int d = 0; d < dim; ++d) + shapes[j * n_shapes + i][0][d] = result[j * dim + d]; + } + } + + + /** * Interpolate inner dimensions of tensor product shape functions. */