[{"id":29454,"web_url":"https://patchwork.libcamera.org/comment/29454/","msgid":"<20240508152318.GC19625@pendragon.ideasonboard.com>","date":"2024-05-08T15:23:18","subject":"Re: [PATCH v4] ipa: libipa: histogram: Add transform parameter to\n\tconstructor","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Paul,\n\nThank you for the patch.\n\nOn Wed, May 08, 2024 at 11:59:24PM +0900, Paul Elder wrote:\n> Add a parameter to the histogram constructor that takes a transformation\n> function to apply to all the bins upon construction.\n> \n> This is necessary notably for the rkisp1, as the values reported from\n> the hardware are 20 bits where the upper 16-bits are meaningful integer\n> values and the lower 4 bits are fractional and meant to be discarded. As\n> adding a right-shift parameter is probably too specialized, a generic\n> function is added as a parameter instead.\n> \n> Signed-off-by: Paul Elder \n> Reviewed-by: Kieran Bingham \n> Reviewed-by: Daniel Scally \n> \n> ---\n> Changes in v4:\n> - fix compilation when called with no transform function\n> \n> Changes in v3:\n> - make the transform function a template parameter, and optimize the\n> constructor\n> \n> This used to be \"ipa: libipa: histogram: Add rshift parameter to\n> constructor\"\n> \n> Changes in v2:\n> - change rshift parameter to a function parameter\n> ---\n> src/ipa/libipa/histogram.cpp | 14 ++++++++++----\n> src/ipa/libipa/histogram.h | 13 ++++++++++++-\n> 2 files changed, 22 insertions(+), 5 deletions(-)\n> \n> diff --git a/src/ipa/libipa/histogram.cpp b/src/ipa/libipa/histogram.cpp\n> index c1aac59b..212acfdf 100644\n> --- a/src/ipa/libipa/histogram.cpp\n> +++ b/src/ipa/libipa/histogram.cpp\n> @@ -43,12 +43,18 @@ namespace ipa {\n> */\n> Histogram::Histogram(Span data)\n> {\n> -\tcumulative_.reserve(data.size());\n> -\tcumulative_.push_back(0);\n> -\tfor (const uint32_t &value : data)\n> -\t\tcumulative_.push_back(cumulative_.back() + value);\n> +\tcumulative_.resize(data.size() + 1);\n> +\tcumulative_[0] = 0;\n> +\tfor (const auto &[i, value] : utils::enumerate(data))\n> +\t\tcumulative_[i + 1] = cumulative_[i] + value;\n\nThis is a nice optimization. I would have split it to another patch\nthough, or at least mentioned it in the commit message.\n\n> }\n> \n> +/**\n> + * \\brief Create a cumulative histogram\n> + * \\param[in] data A pre-sorted histogram to be passed\n\nLooks like there's room for improvement in the existing documentation of\nthe constructor. \"pre-sorted\" doesn't make too much sense here, and\nneither does \"to be passed\".\n\n> + * \\param[in] transform The transformation function to apply to every bin\n> + */\n> +\n> /**\n> * \\fn Histogram::bins()\n> * \\brief Retrieve the number of bins currently used by the Histogram\n> diff --git a/src/ipa/libipa/histogram.h b/src/ipa/libipa/histogram.h\n> index 54bb2a19..0e9bef2a 100644\n> --- a/src/ipa/libipa/histogram.h\n> +++ b/src/ipa/libipa/histogram.h\n> @@ -10,10 +10,10 @@\n> #include \n> #include \n> #include \n\nYou need to include for std::enable_if_t and\nstd::is_invocable_v.\n\nWith these small issues fixed,\n\nReviewed-by: Laurent Pinchart \n\n> -\n> #include \n> \n> #include \n> +#include \n> \n> namespace libcamera {\n> \n> @@ -24,6 +24,17 @@ class Histogram\n> public:\n> \tHistogram() { cumulative_.push_back(0); }\n> \tHistogram(Span data);\n> +\n> +\ttemplate +\t\t std::enable_if_t> * = nullptr>\n> +\tHistogram(Span data, Transform transform)\n> +\t{\n> +\t\tcumulative_.resize(data.size() + 1);\n> +\t\tcumulative_[0] = 0;\n> +\t\tfor (const auto &[i, value] : utils::enumerate(data))\n> +\t\t\tcumulative_[i + 1] = cumulative_[i] + transform(value);\n> +\t}\n> +\n> \tsize_t bins() const { return cumulative_.size() - 1; }\n> \tuint64_t total() const { return cumulative_[cumulative_.size() - 1]; }\n> \tuint64_t cumulativeFrequency(double bin) const;","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 70404BDE6B\n\tfor ;\n\tWed, 8 May 2024 15:23:29 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 2DFC863437;\n\tWed, 8 May 2024 17:23:28 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 4AED861A73\n\tfor ;\n\tWed, 8 May 2024 17:23:27 +0200 (CEST)","from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi\n\t[81.175.209.231])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id E2081FD6;\n\tWed, 8 May 2024 17:23:23 +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=\"a/PYm1UB\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1715181804;\n\tbh=8sAmqAetGjWvn9Uyt1jpjKmteZsvDRPJ/p+nOoe/gWM=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=a/PYm1UBQKvkbBy+DQklghS9iC0WoVyrzPO3TssLiZozkzL7j6CWrjd5IUD/y6G5M\n\tvOQ8QchhJL4KE/AqzniFmiZA3pwC5yRj2/8QqZ1j+YZuAH+6NOTGOuqgkZ/pyE25Jb\n\t2aNtVM2AZ8LWZVL7NpKHFs5PtS7NCuvUYXuWtimA=","Date":"Wed, 8 May 2024 18:23:18 +0300","From":"Laurent Pinchart ","To":"Paul Elder ","Cc":"libcamera-devel@lists.libcamera.org,\n\tKieran Bingham ,\n\tDaniel Scally ","Subject":"Re: [PATCH v4] ipa: libipa: histogram: Add transform parameter to\n\tconstructor","Message-ID":"<20240508152318.GC19625@pendragon.ideasonboard.com>","References":"<20240508145924.1477599-1-paul.elder@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20240508145924.1477599-1-paul.elder@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\" "}},{"id":29466,"web_url":"https://patchwork.libcamera.org/comment/29466/","msgid":"","date":"2024-05-09T06:17:01","subject":"Re: [PATCH v4] ipa: libipa: histogram: Add transform parameter to\n\tconstructor","submitter":{"id":17,"url":"https://patchwork.libcamera.org/api/people/17/","name":"Paul Elder","email":"paul.elder@ideasonboard.com"},"content":"On Wed, May 08, 2024 at 06:23:18PM +0300, Laurent Pinchart wrote:\n> Hi Paul,\n> \n> Thank you for the patch.\n> \n> On Wed, May 08, 2024 at 11:59:24PM +0900, Paul Elder wrote:\n> > Add a parameter to the histogram constructor that takes a transformation\n> > function to apply to all the bins upon construction.\n> > \n> > This is necessary notably for the rkisp1, as the values reported from\n> > the hardware are 20 bits where the upper 16-bits are meaningful integer\n> > values and the lower 4 bits are fractional and meant to be discarded. As\n> > adding a right-shift parameter is probably too specialized, a generic\n> > function is added as a parameter instead.\n> > \n> > Signed-off-by: Paul Elder \n> > Reviewed-by: Kieran Bingham \n> > Reviewed-by: Daniel Scally \n> > \n> > ---\n> > Changes in v4:\n> > - fix compilation when called with no transform function\n> > \n> > Changes in v3:\n> > - make the transform function a template parameter, and optimize the\n> > constructor\n> > \n> > This used to be \"ipa: libipa: histogram: Add rshift parameter to\n> > constructor\"\n> > \n> > Changes in v2:\n> > - change rshift parameter to a function parameter\n> > ---\n> > src/ipa/libipa/histogram.cpp | 14 ++++++++++----\n> > src/ipa/libipa/histogram.h | 13 ++++++++++++-\n> > 2 files changed, 22 insertions(+), 5 deletions(-)\n> > \n> > diff --git a/src/ipa/libipa/histogram.cpp b/src/ipa/libipa/histogram.cpp\n> > index c1aac59b..212acfdf 100644\n> > --- a/src/ipa/libipa/histogram.cpp\n> > +++ b/src/ipa/libipa/histogram.cpp\n> > @@ -43,12 +43,18 @@ namespace ipa {\n> > */\n> > Histogram::Histogram(Span data)\n> > {\n> > -\tcumulative_.reserve(data.size());\n> > -\tcumulative_.push_back(0);\n> > -\tfor (const uint32_t &value : data)\n> > -\t\tcumulative_.push_back(cumulative_.back() + value);\n> > +\tcumulative_.resize(data.size() + 1);\n> > +\tcumulative_[0] = 0;\n> > +\tfor (const auto &[i, value] : utils::enumerate(data))\n> > +\t\tcumulative_[i + 1] = cumulative_[i] + value;\n> \n> This is a nice optimization. I would have split it to another patch\n> though, or at least mentioned it in the commit message.\n> \n\nOh yeah true.\n\n> > }\n> > \n> > +/**\n> > + * \\brief Create a cumulative histogram\n> > + * \\param[in] data A pre-sorted histogram to be passed\n> \n> Looks like there's room for improvement in the existing documentation of\n> the constructor. \"pre-sorted\" doesn't make too much sense here, and\n> neither does \"to be passed\".\n\n\"But it does have to be pre-sorted... oh wait, we're passing in a\nnon-cumulative histogram... so it's already sorted by definition... ok\nI see\"\n\n> \n> > + * \\param[in] transform The transformation function to apply to every bin\n> > + */\n> > +\n> > /**\n> > * \\fn Histogram::bins()\n> > * \\brief Retrieve the number of bins currently used by the Histogram\n> > diff --git a/src/ipa/libipa/histogram.h b/src/ipa/libipa/histogram.h\n> > index 54bb2a19..0e9bef2a 100644\n> > --- a/src/ipa/libipa/histogram.h\n> > +++ b/src/ipa/libipa/histogram.h\n> > @@ -10,10 +10,10 @@\n> > #include \n> > #include \n> > #include \n> \n> You need to include for std::enable_if_t and\n> std::is_invocable_v.\n\nack\n\n> \n> With these small issues fixed,\n> \n> Reviewed-by: Laurent Pinchart \n\nThanks,\n\nPaul\n\n> \n> > -\n> > #include \n> > \n> > #include \n> > +#include \n> > \n> > namespace libcamera {\n> > \n> > @@ -24,6 +24,17 @@ class Histogram\n> > public:\n> > \tHistogram() { cumulative_.push_back(0); }\n> > \tHistogram(Span data);\n> > +\n> > +\ttemplate > +\t\t std::enable_if_t> * = nullptr>\n> > +\tHistogram(Span data, Transform transform)\n> > +\t{\n> > +\t\tcumulative_.resize(data.size() + 1);\n> > +\t\tcumulative_[0] = 0;\n> > +\t\tfor (const auto &[i, value] : utils::enumerate(data))\n> > +\t\t\tcumulative_[i + 1] = cumulative_[i] + transform(value);\n> > +\t}\n> > +\n> > \tsize_t bins() const { return cumulative_.size() - 1; }\n> > \tuint64_t total() const { return cumulative_[cumulative_.size() - 1]; }\n> > \tuint64_t cumulativeFrequency(double bin) const;\n> \n> -- \n> Regards,\n> \n> Laurent Pinchart","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 41E76BDE6B\n\tfor ;\n\tThu, 9 May 2024 06:17:12 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 604336345F;\n\tThu, 9 May 2024 08:17:11 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 31F6D61A6B\n\tfor ;\n\tThu, 9 May 2024 08:17:09 +0200 (CEST)","from pyrite.rasen.tech (h175-177-049-156.catv02.itscom.jp\n\t[175.177.49.156])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 3615E2D54;\n\tThu, 9 May 2024 08:17:03 +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=\"R6AFcWcy\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1715235425;\n\tbh=V4sNwMGbq/Vj86Wk8ViP7VUpQ/pvsYGySYa2tddVINw=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=R6AFcWcyYM/kgL0scHYAq/0DV3ga5/c7Pc6pfVyx1XWZBpSYrGpeKOY5mO6xZZw7o\n\tRJNx0PMGie8/FqbK4KmBPuwLRu7pywsmLMH5bA5eLj07jKAXYNRBdHfTGI1zBJSWrw\n\tJuhemhaPQUnkoocnho+l3WVwg5CXZlRz/AY9Bo6g=","Date":"Thu, 9 May 2024 15:17:01 +0900","From":"Paul Elder ","To":"Laurent Pinchart ","Cc":"libcamera-devel@lists.libcamera.org,\n\tKieran Bingham ,\n\tDaniel Scally ","Subject":"Re: [PATCH v4] ipa: libipa: histogram: Add transform parameter to\n\tconstructor","Message-ID":"","References":"<20240508145924.1477599-1-paul.elder@ideasonboard.com>\n\t<20240508152318.GC19625@pendragon.ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=us-ascii","Content-Disposition":"inline","In-Reply-To":"<20240508152318.GC19625@pendragon.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\" "}}]