From ee1d93d8aa718843eebac33a8d568a3ae2efa54c Mon Sep 17 00:00:00 2001
From: Stefan Klug <stefan.klug@ideasonboard.com>
Date: Wed, 28 Jan 2026 17:00:27 +0100
Subject: [PATCH] ipa: libipa: interpolator: Drop key quantization
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The quantization of the interpolation key was only used by the LSC
algorithm. There it lead to difficult to read code was removed. As there
is no remaining user of it, drop it from the Interpolator class.

While at it, cleanup the includes.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
---
 src/ipa/libipa/interpolator.cpp  | 25 +------------------------
 src/ipa/libipa/interpolator.h    | 14 +-------------
 test/ipa/libipa/interpolator.cpp |  7 -------
 3 files changed, 2 insertions(+), 44 deletions(-)

diff --git a/src/ipa/libipa/interpolator.cpp b/src/ipa/libipa/interpolator.cpp
index f901a86e..00bf66b6 100644
--- a/src/ipa/libipa/interpolator.cpp
+++ b/src/ipa/libipa/interpolator.cpp
@@ -6,15 +6,8 @@
  */
 #include "interpolator.h"
 
-#include <algorithm>
-#include <string>
-
 #include <libcamera/base/log.h>
 
-#include "libcamera/internal/yaml_parser.h"
-
-#include "interpolator.h"
-
 /**
  * \file interpolator.h
  * \brief Helper class for linear interpolating a set of objects
@@ -104,20 +97,6 @@ namespace ipa {
  * \return Zero on success, negative error code otherwise
  */
 
-/**
- * \fn void Interpolator<T>::setQuantization(const unsigned int q)
- * \brief Set the quantization value
- * \param[in] q The quantization value
- *
- * Sets the quantization value. When this is set, 'key' gets quantized to this
- * size, before doing the interpolation. This can help in reducing the number of
- * updates pushed to the hardware.
- *
- * Note that normally a threshold needs to be combined with quantization.
- * Otherwise a value that swings around the edge of the quantization step will
- * lead to constant updates.
- */
-
 /**
  * \fn void Interpolator<T>::setData(std::map<unsigned int, T> &&data)
  * \brief Set the internal map
@@ -136,10 +115,8 @@ namespace ipa {
  * \fn const T& Interpolator<T>::getInterpolated()
  * \brief Retrieve an interpolated value for the given key
  * \param[in] key The unsigned integer key of the object to retrieve
- * \param[out] quantizedKey If provided, the key value after quantization
  * \return The object corresponding to the key. The object is cached internally,
- * so on successive calls with the same key (after quantization) interpolation
- * is not recalculated.
+ * so on successive calls with the same key interpolation is not recalculated.
  */
 
 /**
diff --git a/src/ipa/libipa/interpolator.h b/src/ipa/libipa/interpolator.h
index 7880db69..fb2c611d 100644
--- a/src/ipa/libipa/interpolator.h
+++ b/src/ipa/libipa/interpolator.h
@@ -70,11 +70,6 @@ public:
 		return 0;
 	}
 
-	void setQuantization(const unsigned int q)
-	{
-		quantization_ = q;
-	}
-
 	void setData(std::map<unsigned int, T> &&data)
 	{
 		data_ = std::move(data);
@@ -86,16 +81,10 @@ public:
 		return data_;
 	}
 
-	const T &getInterpolated(unsigned int key, unsigned int *quantizedKey = nullptr)
+	const T &getInterpolated(unsigned int key)
 	{
 		ASSERT(data_.size() > 0);
 
-		if (quantization_ > 0)
-			key = std::lround(key / static_cast<double>(quantization_)) * quantization_;
-
-		if (quantizedKey)
-			*quantizedKey = key;
-
 		if (lastInterpolatedKey_.has_value() &&
 		    *lastInterpolatedKey_ == key)
 			return lastInterpolatedValue_;
@@ -128,7 +117,6 @@ private:
 	std::map<unsigned int, T> data_;
 	T lastInterpolatedValue_;
 	std::optional<unsigned int> lastInterpolatedKey_;
-	unsigned int quantization_ = 0;
 };
 
 } /* namespace ipa */
diff --git a/test/ipa/libipa/interpolator.cpp b/test/ipa/libipa/interpolator.cpp
index 6abb7760..03b7089a 100644
--- a/test/ipa/libipa/interpolator.cpp
+++ b/test/ipa/libipa/interpolator.cpp
@@ -40,13 +40,6 @@ protected:
 		ASSERT_EQ(interpolator.getInterpolated(30), 300);
 		ASSERT_EQ(interpolator.getInterpolated(40), 300);
 
-		interpolator.setQuantization(10);
-		unsigned int q = 0;
-		ASSERT_EQ(interpolator.getInterpolated(25, &q), 300);
-		ASSERT_EQ(q, 30);
-		ASSERT_EQ(interpolator.getInterpolated(24, &q), 200);
-		ASSERT_EQ(q, 20);
-
 		return TestPass;
 	}
 };