From a9e4dc98c4f113c42946a1a437b60f43f1a81f30 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Lema=C5=84czyk?= <marek@lemanczyk.eu>
Date: Sat, 20 Sep 2025 09:39:53 +0200
Subject: [PATCH] Revert "Merge pull request #38 from
 mlemanczyk/codex/fix-residue-method-iteration-issue"

This reverts commit afcc8d87f98f1a341b8d03d59ed76bd96a61db26, reversing
changes made to 5702e45169ff2016efa7719717b1332910def866.
---
 .../ResidueCandidateEnumerationTests.cs       | 77 -------------------
 EvenPerfectBitScanner/Program.cs              |  6 --
 2 files changed, 83 deletions(-)
 delete mode 100644 EvenPerfectBitScanner.Tests/ResidueCandidateEnumerationTests.cs

diff --git a/EvenPerfectBitScanner.Tests/ResidueCandidateEnumerationTests.cs b/EvenPerfectBitScanner.Tests/ResidueCandidateEnumerationTests.cs
deleted file mode 100644
index 8d65839..0000000
--- a/EvenPerfectBitScanner.Tests/ResidueCandidateEnumerationTests.cs
+++ /dev/null
@@ -1,77 +0,0 @@
-using System;
-using System.Threading;
-using EvenPerfectBitScanner;
-using PerfectNumbers.Core;
-using Xunit;
-
-namespace EvenPerfectBitScanner.Tests;
-
-public class ResidueCandidateEnumerationTests
-{
-    [Fact]
-    public void ModResidueTracker_does_not_flag_small_primes_as_composite()
-    {
-        var tracker = new ModResidueTracker(ResidueModel.Identity, initialNumber: 13UL, initialized: true);
-        var primes = PrimesGenerator.SmallPrimes;
-        var primesPow2 = PrimesGenerator.SmallPrimesPow2;
-
-        ulong p = 13UL;
-        ulong remainder = p % 6UL;
-
-        for (int i = 0; i < 2000; i++)
-        {
-            tracker.BeginMerge(p);
-            bool composite = false;
-            for (int j = 0; j < primes.Length; j++)
-            {
-                if (primesPow2[j] > p)
-                {
-                    break;
-                }
-
-                tracker.MergeOrAppend(p, primes[j], out bool divisible);
-                if (divisible)
-                {
-                    composite = true;
-                    break;
-                }
-            }
-
-            bool isPrime = PrimeTester.IsPrimeInternal(p, CancellationToken.None);
-            if (isPrime && composite)
-            {
-                throw new InvalidOperationException($"Prime {p} marked as composite.");
-            }
-
-            p = Program.TransformPAdd(p, ref remainder);
-        }
-    }
-
-    [Fact]
-    public void TransformPAdd_visits_both_prime_residue_classes()
-    {
-        ulong p = 13UL;
-        ulong remainder = p % 6UL;
-        bool sawOneModSix = false;
-        bool sawFiveModSix = false;
-
-        for (int i = 0; i < 256; i++)
-        {
-            ulong residue = p % 6UL;
-            if (residue == 1UL)
-            {
-                sawOneModSix = true;
-            }
-            else if (residue == 5UL)
-            {
-                sawFiveModSix = true;
-            }
-
-            p = Program.TransformPAdd(p, ref remainder);
-        }
-
-        Assert.True(sawOneModSix, "Sequence never produced numbers congruent to 1 mod 6.");
-        Assert.True(sawFiveModSix, "Sequence never produced numbers congruent to 5 mod 6.");
-    }
-
-}
diff --git a/EvenPerfectBitScanner/Program.cs b/EvenPerfectBitScanner/Program.cs
index 1e9a6ab..681e3cc 100644
--- a/EvenPerfectBitScanner/Program.cs
+++ b/EvenPerfectBitScanner/Program.cs
@@ -554,12 +554,6 @@ internal static class Program
 		}
 
 		bool useFilter = !string.IsNullOrEmpty(filterFile);
-		if (useFilter && !useBitTransform)
-		{
-			// When replaying a filtered list of p values, iterate strictly along the prime sequence.
-			// This keeps candidate generation aligned with the recorded primes regardless of residue stepping.
-			_transformP = &TransformPAddPrimes;
-		}
 		HashSet<ulong> filter = [];
 		ulong maxP = 0UL;
 		if (useFilter)