From 46153c59b2b8017e3ca249e2f4e6dc62d326c2fb Mon Sep 17 00:00:00 2001
From: Ahmet Inan <inan@aicodix.de>
Date: Sun, 28 Dec 2025 10:15:55 +0100
Subject: [PATCH] renamed and updated Bhattacharyya code construction

---
 polar_sequence.hh                     | 8 ++++----
 tests/pac_list_regression_test.cc     | 4 ++--
 tests/polar_list_regression_test.cc   | 4 ++--
 tests/polar_parity_regression_test.cc | 4 ++--
 tests/polar_regression_test.cc        | 4 ++--
 5 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/polar_sequence.hh b/polar_sequence.hh
index 511129d..90a3096 100644
--- a/polar_sequence.hh
+++ b/polar_sequence.hh
@@ -6,12 +6,12 @@ Copyright 2023 Ahmet Inan <inan@aicodix.de>
 
 #pragma once
 
-#include <algorithm>
+#include "sort.hh"
 
 namespace CODE {
 
 template <int MAX_M>
-class PolarSeqConst0
+class BhattacharyyaSequence
 {
 	void compute(double pe, int i, int h)
 	{
@@ -23,7 +23,7 @@ class PolarSeqConst0
 		}
 	}
 	double prob[1<<MAX_M];
-	int index[1<<MAX_M];
+	MergeSort<int, 1<<MAX_M> sort;
 public:
 	void operator()(int *sequence, int level, double erasure_probability = std::exp(-1.))
 	{
@@ -32,7 +32,7 @@ public:
 		compute(erasure_probability, 0, length / 2);
 		for (int i = 0; i < length; ++i)
 			sequence[i] = i;
-		std::sort(sequence, sequence+length, [this](int a, int b){ return prob[a] > prob[b]; });
+		sort(sequence, length, [this](int a, int b){ return prob[a] > prob[b]; });
 	}
 };
 
diff --git a/tests/pac_list_regression_test.cc b/tests/pac_list_regression_test.cc
index 8fe7b56..be4e209 100644
--- a/tests/pac_list_regression_test.cc
+++ b/tests/pac_list_regression_test.cc
@@ -54,8 +54,8 @@ int main()
 	double design_SNR = 10 * std::log10(-std::log(erasure_probability));
 	std::cerr << "design SNR: " << design_SNR << std::endl;
 	if (1) {
-		auto construct = new CODE::PolarSeqConst0<M>;
-		std::cerr << "sizeof(PolarSeqConst0<M>) = " << sizeof(CODE::PolarSeqConst0<M>) << std::endl;
+		auto construct = new CODE::BhattacharyyaSequence<M>;
+		std::cerr << "sizeof(BhattacharyyaSequence<M>) = " << sizeof(CODE::BhattacharyyaSequence<M>) << std::endl;
 		double better_SNR = design_SNR + 1.59175;
 		std::cerr << "better SNR: " << better_SNR << std::endl;
 		double probability = std::exp(-pow(10.0, better_SNR / 10));
diff --git a/tests/polar_list_regression_test.cc b/tests/polar_list_regression_test.cc
index 95437c3..e1d9c72 100644
--- a/tests/polar_list_regression_test.cc
+++ b/tests/polar_list_regression_test.cc
@@ -56,8 +56,8 @@ int main()
 	double design_SNR = 10 * std::log10(-std::log(erasure_probability));
 	std::cerr << "design SNR: " << design_SNR << std::endl;
 	if (1) {
-		auto construct = new CODE::PolarSeqConst0<M>;
-		std::cerr << "sizeof(PolarSeqConst0<M>) = " << sizeof(CODE::PolarSeqConst0<M>) << std::endl;
+		auto construct = new CODE::BhattacharyyaSequence<M>;
+		std::cerr << "sizeof(BhattacharyyaSequence<M>) = " << sizeof(CODE::BhattacharyyaSequence<M>) << std::endl;
 		double better_SNR = design_SNR + 1.59175;
 		std::cerr << "better SNR: " << better_SNR << std::endl;
 		double probability = std::exp(-pow(10.0, better_SNR / 10));
diff --git a/tests/polar_parity_regression_test.cc b/tests/polar_parity_regression_test.cc
index e4a22a3..d02ebb1 100644
--- a/tests/polar_parity_regression_test.cc
+++ b/tests/polar_parity_regression_test.cc
@@ -54,8 +54,8 @@ int main()
 	double design_SNR = 10 * std::log10(-std::log(erasure_probability));
 	std::cerr << "design SNR: " << design_SNR << std::endl;
 	if (1) {
-		auto construct = new CODE::PolarSeqConst0<M>;
-		std::cerr << "sizeof(PolarSeqConst0<M>) = " << sizeof(CODE::PolarSeqConst0<M>) << std::endl;
+		auto construct = new CODE::BhattacharyyaSequence<M>;
+		std::cerr << "sizeof(BhattacharyyaSequence<M>) = " << sizeof(CODE::BhattacharyyaSequence<M>) << std::endl;
 		double better_SNR = design_SNR + 1.59175;
 		std::cerr << "better SNR: " << better_SNR << std::endl;
 		double probability = std::exp(-pow(10.0, better_SNR / 10));
diff --git a/tests/polar_regression_test.cc b/tests/polar_regression_test.cc
index 3e1dafa..c006bec 100644
--- a/tests/polar_regression_test.cc
+++ b/tests/polar_regression_test.cc
@@ -56,8 +56,8 @@ int main()
 		delete freeze;
 	} else {
 		auto sequence = new int[N];
-		auto construct = new CODE::PolarSeqConst0<M>;
-		std::cerr << "sizeof(PolarSeqConst0<M>) = " << sizeof(CODE::PolarSeqConst0<M>) << std::endl;
+		auto construct = new CODE::BhattacharyyaSequence<M>;
+		std::cerr << "sizeof(BhattacharyyaSequence<M>) = " << sizeof(CODE::BhattacharyyaSequence<M>) << std::endl;
 		(*construct)(sequence, M, probability);
 		delete construct;
 		for (int i = 0; i < N / 32; ++i)