ipa: libipa: Add Matrix class

Add a class to represent a Matrix object and operations for adding
matrices, multipling a matrix by a scalar, and multiplying two matrices.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 204 insertions, 0 deletions

diff --git a/src/ipa/libipa/matrix.h b/src/ipa/libipa/matrix.h
new file mode 100644
index 00000000..8aa8f343
--- /dev/null
+++ b/src/ipa/libipa/matrix.h
@@ -0,0 +1,204 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Paul Elder <paul.elder@ideasonboard.com>
+ *
+ * Matrix and related operations
+ */
+#pragma once
+
+#include <algorithm>
+#include <cmath>
+#include <sstream>
+#include <vector>
+
+#include <libcamera/base/log.h>
+#include <libcamera/base/span.h>
+
+#include "libcamera/internal/yaml_parser.h"
+
+namespace libcamera {
+
+LOG_DECLARE_CATEGORY(Matrix)
+
+namespace ipa {
+
+#ifndef __DOXYGEN__
+template<typename T, unsigned int Rows, unsigned int Cols,
+	 std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
+#else
+template<typename T, unsigned int Rows, unsigned int Cols>
+#endif /* __DOXYGEN__ */
+class Matrix
+{
+public:
+	Matrix()
+	{
+		data_.fill(static_cast<T>(0));
+	}
+
+	Matrix(const std::vector<T> &data)
+	{
+		std::copy(data.begin(), data.end(), data_.begin());
+	}
+
+	static Matrix identity()
+	{
+		Matrix ret;
+		for (size_t i = 0; i < std::min(Rows, Cols); i++)
+			ret[i][i] = static_cast<T>(1);
+		return ret;
+	}
+
+	~Matrix() = default;
+
+	const std::string toString() const
+	{
+		std::stringstream out;
+
+		out << "Matrix { ";
+		for (unsigned int i = 0; i < Rows; i++) {
+			out << "[ ";
+			for (unsigned int j = 0; j < Cols; j++) {
+				out << (*this)[i][j];
+				out << ((j + 1 < Cols) ? ", " : " ");
+			}
+			out << ((i + 1 < Rows) ? "], " : "]");
+		}
+		out << " }";
+
+		return out.str();
+	}
+
+	Span<const T, Cols> operator[](size_t i) const
+	{
+		return Span<const T, Cols>{ &data_.data()[i * Cols], Cols };
+	}
+
+	Span<T, Cols> operator[](size_t i)
+	{
+		return Span<T, Cols>{ &data_.data()[i * Cols], Cols };
+	}
+
+#ifndef __DOXYGEN__
+	template<typename U, std::enable_if_t<std::is_arithmetic_v<U>>>
+#else
+	template<typename U>
+#endif /* __DOXYGEN__ */
+	Matrix<T, Rows, Cols> &operator*=(U d)
+	{
+		for (unsigned int i = 0; i < Rows * Cols; i++)
+			data_[i] *= d;
+		return *this;
+	}
+
+private:
+	std::array<T, Rows * Cols> data_;
+};
+
+#ifndef __DOXYGEN__
+template<typename T, typename U, unsigned int Rows, unsigned int Cols,
+	 std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
+#else
+template<typename T, typename U, unsigned int Rows, unsigned int Cols>
+#endif /* __DOXYGEN__ */
+Matrix<U, Rows, Cols> operator*(T d, const Matrix<U, Rows, Cols> &m)
+{
+	Matrix<U, Rows, Cols> result;
+
+	for (unsigned int i = 0; i < Rows; i++) {
+		for (unsigned int j = 0; j < Cols; j++)
+			result[i][j] = d * m[i][j];
+	}
+
+	return result;
+}
+
+#ifndef __DOXYGEN__
+template<typename T, typename U, unsigned int Rows, unsigned int Cols,
+	 std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
+#else
+template<typename T, typename U, unsigned int Rows, unsigned int Cols>
+#endif /* __DOXYGEN__ */
+Matrix<U, Rows, Cols> operator*(const Matrix<U, Rows, Cols> &m, T d)
+{
+	return d * m;
+}
+
+#ifndef __DOXYGEN__
+template<typename T,
+	 unsigned int R1, unsigned int C1,
+	 unsigned int R2, unsigned int C2,
+	 std::enable_if_t<C1 == R2> * = nullptr>
+#else
+template<typename T, unsigned int R1, unsigned int C1, unsigned int R2, unsigned in C2>
+#endif /* __DOXYGEN__ */
+Matrix<T, R1, C2> operator*(const Matrix<T, R1, C1> &m1, const Matrix<T, R2, C2> &m2)
+{
+	Matrix<T, R1, C2> result;
+
+	for (unsigned int i = 0; i < R1; i++) {
+		for (unsigned int j = 0; j < C2; j++) {
+			T sum = 0;
+
+			for (unsigned int k = 0; k < C1; k++)
+				sum += m1[i][k] * m2[k][j];
+
+			result[i][j] = sum;
+		}
+	}
+
+	return result;
+}
+
+template<typename T, unsigned int Rows, unsigned int Cols>
+Matrix<T, Rows, Cols> operator+(const Matrix<T, Rows, Cols> &m1, const Matrix<T, Rows, Cols> &m2)
+{
+	Matrix<T, Rows, Cols> result;
+
+	for (unsigned int i = 0; i < Rows; i++) {
+		for (unsigned int j = 0; j < Cols; j++)
+			result[i][j] = m1[i][j] + m2[i][j];
+	}
+
+	return result;
+}
+
+#ifndef __DOXYGEN__
+bool matrixValidateYaml(const YamlObject &obj, unsigned int size);
+#endif /* __DOXYGEN__ */
+
+} /* namespace ipa */
+
+#ifndef __DOXYGEN__
+template<typename T, unsigned int Rows, unsigned int Cols>
+std::ostream &operator<<(std::ostream &out, const ipa::Matrix<T, Rows, Cols> &m)
+{
+	out << m.toString();
+	return out;
+}
+
+template<typename T, unsigned int Rows, unsigned int Cols>
+struct YamlObject::Getter<ipa::Matrix<T, Rows, Cols>> {
+	std::optional<ipa::Matrix<T, Rows, Cols>> get(const YamlObject &obj) const
+	{
+		if (!ipa::matrixValidateYaml(obj, Rows * Cols))
+			return std::nullopt;
+
+		ipa::Matrix<T, Rows, Cols> matrix;
+		T *data = &matrix[0][0];
+
+		unsigned int i = 0;
+		for (const YamlObject &entry : obj.asList()) {
+			const auto value = entry.get<T>();
+			if (!value)
+				return std::nullopt;
+
+			data[i++] = *value;
+		}
+
+		return matrix;
+	}
+};
+#endif /* __DOXYGEN__ */
+
+} /* namespace libcamera */