From 5ca10480b0756e40b0723d90adeba8506291fc7c Mon Sep 17 00:00:00 2001 From: Francesco Mazzoli Date: Mon, 13 Jan 2020 15:11:22 +0100 Subject: [PATCH] avoid selecting half-packets when unnecessary See for an explanation of the problem this solves. In short, for some reason, before this commit the half-packet is selected when the array / matrix size is not a multiple of `unpacket_traits::size`, where `PacketType` starts out being the full Packet. For example, for some data of 100 `float`s, `Packet4f` will be selected rather than `Packet8f`, because 100 is not a multiple of 8, the size of `Packet8f`. This commit switches to selecting the half-packet if the size is less than the packet size, which seems to make more sense. As I stated in the SO post I'm not sure that I'm understanding the issue correctly, but this fix resolves the issue in my program. Moreover, `make check` passes, with the exception of line 614 and 616 in `test/packetmath.cpp`, which however also fail on master on my machine: CHECK_CWISE1_IF(PacketTraits::HasBessel, numext::bessel_i0, internal::pbessel_i0); ... CHECK_CWISE1_IF(PacketTraits::HasBessel, numext::bessel_i1, internal::pbessel_i1); --- Eigen/src/Core/util/XprHelper.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Eigen/src/Core/util/XprHelper.h b/Eigen/src/Core/util/XprHelper.h index fd2db56a4..26aa609fe 100644 --- a/Eigen/src/Core/util/XprHelper.h +++ b/Eigen/src/Core/util/XprHelper.h @@ -195,7 +195,7 @@ template struct unpacket_traits }; template::size)==0 || is_same::half>::value> + bool Stop = Size==Dynamic || Size >= unpacket_traits::size || is_same::half>::value> struct find_best_packet_helper; template< int Size, typename PacketType>