From 9c49101420c27b4cda975b36cdeed901d9f083e1 Mon Sep 17 00:00:00 2001
From: Relintai <relintai@protonmail.com>
Date: Mon, 13 Feb 2023 17:23:25 +0100
Subject: [PATCH] Added MLPPTransformsOld.

---
 SCsub                              |  1 +
 mlpp/transforms/transforms_old.cpp | 56 ++++++++++++++++++++++++++++++
 mlpp/transforms/transforms_old.h   | 27 ++++++++++++++
 3 files changed, 84 insertions(+)
 create mode 100644 mlpp/transforms/transforms_old.cpp
 create mode 100644 mlpp/transforms/transforms_old.h

diff --git a/SCsub b/SCsub
index 7dd2803..1dcbe50 100644
--- a/SCsub
+++ b/SCsub
@@ -79,6 +79,7 @@ sources = [
     "mlpp/regularization/reg_old.cpp",
     "mlpp/gauss_markov_checker/gauss_markov_checker_old.cpp",
     "mlpp/utilities/utilities_old.cpp",
+    "mlpp/transforms/transforms_old.cpp",
 
     "test/mlpp_tests.cpp",
 ]
diff --git a/mlpp/transforms/transforms_old.cpp b/mlpp/transforms/transforms_old.cpp
new file mode 100644
index 0000000..ffd1962
--- /dev/null
+++ b/mlpp/transforms/transforms_old.cpp
@@ -0,0 +1,56 @@
+//
+//  Transforms.cpp
+//
+//  Created by Marc Melikyan on 11/13/20.
+//
+
+#include "transforms_old.h"
+#include "../lin_alg/lin_alg.h"
+#include <cmath>
+#include <iostream>
+#include <string>
+
+// DCT ii.
+// https://www.mathworks.com/help/images/discrete-cosine-transform.html
+std::vector<std::vector<real_t>> MLPPTransformsOld::discreteCosineTransform(std::vector<std::vector<real_t>> A) {
+	MLPPLinAlg alg;
+	A = alg.scalarAdd(-128, A); // Center around 0.
+
+	std::vector<std::vector<real_t>> B;
+	B.resize(A.size());
+	for (uint32_t i = 0; i < B.size(); i++) {
+		B[i].resize(A[i].size());
+	}
+
+	int M = A.size();
+
+	for (uint32_t i = 0; i < B.size(); i++) {
+		for (uint32_t j = 0; j < B[i].size(); j++) {
+			real_t sum = 0;
+			real_t alphaI;
+			if (i == 0) {
+				alphaI = 1 / std::sqrt(M);
+			} else {
+				alphaI = std::sqrt(real_t(2) / real_t(M));
+			}
+			real_t alphaJ;
+			if (j == 0) {
+				alphaJ = 1 / std::sqrt(M);
+			} else {
+				alphaJ = std::sqrt(real_t(2) / real_t(M));
+			}
+
+			for (uint32_t k = 0; k < B.size(); k++) {
+				for (uint32_t f = 0; f < B[k].size(); f++) {
+					sum += A[k][f] * std::cos((M_PI * i * (2 * k + 1)) / (2 * M)) * std::cos((M_PI * j * (2 * f + 1)) / (2 * M));
+				}
+			}
+			B[i][j] = sum;
+			B[i][j] *= alphaI * alphaJ;
+		}
+	}
+	return B;
+}
+
+void MLPPTransformsOld::_bind_methods() {
+}
diff --git a/mlpp/transforms/transforms_old.h b/mlpp/transforms/transforms_old.h
new file mode 100644
index 0000000..aabb326
--- /dev/null
+++ b/mlpp/transforms/transforms_old.h
@@ -0,0 +1,27 @@
+
+#ifndef MLPP_TRANSFORMS_OLD_H
+#define MLPP_TRANSFORMS_OLD_H
+
+//
+//  Transforms.hpp
+//
+//
+
+#include "core/math/math_defs.h"
+
+#include "core/object/reference.h"
+
+#include <string>
+#include <vector>
+
+class MLPPTransformsOld : public Reference {
+	GDCLASS(MLPPTransformsOld, Reference);
+
+public:
+	std::vector<std::vector<real_t>> discreteCosineTransform(std::vector<std::vector<real_t>> A);
+
+protected:
+	static void _bind_methods();
+};
+
+#endif /* Transforms_hpp */