[{"id":34145,"web_url":"https://patchwork.libcamera.org/comment/34145/","msgid":"","date":"2025-05-07T16:47:29","subject":"Re: [PATCH v3 08/16] libcamera: vector: Extend matrix multiplication\n\toperator to heterogenous types","submitter":{"id":17,"url":"https://patchwork.libcamera.org/api/people/17/","name":"Paul Elder","email":"paul.elder@ideasonboard.com"},"content":"On Thu, Apr 03, 2025 at 05:49:13PM +0200, Stefan Klug wrote:\n> From: Laurent Pinchart \n> \n> It is useful to multiply matrices and vectors of heterogeneous types, for\n> instance float and double. Extend the multiplication operator to support\n> this, avoiding the need to convert one of the operations. The type of the\n> returned vector is selected automatically to avoid loosing precision.\n> \n> Signed-off-by: Laurent Pinchart \n> Signed-off-by: Stefan Klug \n> Acked-by: Kieran Bingham \n\nReviewed-by: Paul Elder \n\n> \n> ---\n> \n> Changes in v2:\n> - Added this patch\n> \n> Changes in v3:\n> - Collected tag\n> ---\n> include/libcamera/internal/vector.h | 9 +++++----\n> src/libcamera/vector.cpp | 5 +++--\n> 2 files changed, 8 insertions(+), 6 deletions(-)\n> \n> diff --git a/include/libcamera/internal/vector.h b/include/libcamera/internal/vector.h\n> index 4e9ef1ee6853..16b6aef0b38f 100644\n> --- a/include/libcamera/internal/vector.h\n> +++ b/include/libcamera/internal/vector.h\n> @@ -13,6 +13,7 @@\n> #include \n> #include \n> #include \n> +#include \n> \n> #include \n> #include \n> @@ -295,13 +296,13 @@ private:\n> template\n> using RGB = Vector;\n> \n> -template\n> -Vector operator*(const Matrix &m, const Vector &v)\n> +template\n> +Vector, Rows> operator*(const Matrix &m, const Vector &v)\n> {\n> -\tVector result;\n> +\tVector, Rows> result;\n> \n> \tfor (unsigned int i = 0; i < Rows; i++) {\n> -\t\tT sum = 0;\n> +\t\tstd::common_type_t sum = 0;\n> \t\tfor (unsigned int j = 0; j < Cols; j++)\n> \t\t\tsum += m[i][j] * v[j];\n> \t\tresult[i] = sum;\n> diff --git a/src/libcamera/vector.cpp b/src/libcamera/vector.cpp\n> index 5567d5b8defb..4dad1b9001c5 100644\n> --- a/src/libcamera/vector.cpp\n> +++ b/src/libcamera/vector.cpp\n> @@ -308,9 +308,10 @@ LOG_DEFINE_CATEGORY(Vector)\n> */\n> \n> /**\n> - * \\fn Vector operator*(const Matrix &m, const Vector &v)\n> + * \\fn operator*(const Matrix &m, const Vector &v)\n> * \\brief Multiply a matrix by a vector\n> - * \\tparam T Numerical type of the contents of the matrix and vector\n> + * \\tparam T Numerical type of the contents of the matrix\n> + * \\tparam U Numerical type of the contents of the vector\n> * \\tparam Rows The number of rows in the matrix\n> * \\tparam Cols The number of columns in the matrix (= rows in the vector)\n> * \\param m The matrix\n> -- \n> 2.43.0\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id BE652C3200\n\tfor ;\n\tWed, 7 May 2025 16:47:33 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7466468B36;\n\tWed, 7 May 2025 18:47:33 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id B6DA868B2F\n\tfor ;\n\tWed, 7 May 2025 18:47:32 +0200 (CEST)","from pyrite.rasen.tech (unknown\n\t[IPv6:2001:861:3a80:3300:4f2f:8c2c:b3ef:17d4])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 3ABD36D5;\n\tWed, 7 May 2025 18:47:21 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"HFViXO6u\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1746636441;\n\tbh=vLCvZim5VCb3iK9ePbjkG/PYorghkrbE9cOLLvQmZNs=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=HFViXO6uoN0i5jhc7lpYn/kXuK9GpMRjS+Rj+v4hm67alMdtn3NloEPNQjAOaccga\n\tKcaR2KO93yvU5jBjyVTt3ma3BnRoL63VjnCMTAU/gHwCWHM8ke52PUqvXus5WavM3B\n\tr7/v7RKxvjYM7WlfEecHXkrM9KROkRS47tACmpsU=","Date":"Wed, 7 May 2025 18:47:29 +0200","From":"Paul Elder ","To":"Stefan Klug ","Cc":"libcamera-devel@lists.libcamera.org,\n\tLaurent Pinchart ,\n\tKieran Bingham ","Subject":"Re: [PATCH v3 08/16] libcamera: vector: Extend matrix multiplication\n\toperator to heterogenous types","Message-ID":"","References":"<20250403154925.382973-1-stefan.klug@ideasonboard.com>\n\t<20250403154925.382973-9-stefan.klug@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=us-ascii","Content-Disposition":"inline","In-Reply-To":"<20250403154925.382973-9-stefan.klug@ideasonboard.com>","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]