From d555e157f66cfb25b4bbd6057654d79c27ca63ce Mon Sep 17 00:00:00 2001
From: mlemanczyk <marek@lemanczyk.eu>
Date: Sun, 12 Oct 2025 18:23:06 +0200
Subject: [PATCH] Calculation switched to typical O(N)

---
 .../Gpu/PrimeOrderGpuHeuristics.cs            | 88 +++++++++----------
 1 file changed, 44 insertions(+), 44 deletions(-)

diff --git a/PerfectNumbers.Core/Gpu/PrimeOrderGpuHeuristics.cs b/PerfectNumbers.Core/Gpu/PrimeOrderGpuHeuristics.cs
index db03894..b403218 100644
--- a/PerfectNumbers.Core/Gpu/PrimeOrderGpuHeuristics.cs
+++ b/PerfectNumbers.Core/Gpu/PrimeOrderGpuHeuristics.cs
@@ -1812,56 +1812,56 @@ internal static partial class PrimeOrderGpuHeuristics
     {
         ulong exponent = exponents[index];
         ulong modulus = divisor.Modulus;
-        ulong nPrime = divisor.NPrime;
-        ulong result = divisor.MontgomeryOne;
-        ulong baseValue = divisor.MontgomeryTwo;
-        ulong remainingExponent = exponent;
+		// ulong nPrime = divisor.NPrime;
+		// ulong result = divisor.MontgomeryOne;
+		// ulong baseValue = divisor.MontgomeryTwo;
+		// ulong remainingExponent = exponent;
 
-        if (remainingExponent == 0UL)
-        {
-            remainders[index] = result.MontgomeryMultiply(1UL, modulus, nPrime);
-            return;
-        }
+		// if (remainingExponent == 0UL)
+		// {
+		//     remainders[index] = result.MontgomeryMultiply(1UL, modulus, nPrime);
+		//     return;
+		// }
 
-        while (remainingExponent != 0UL)
-        {
-            if ((remainingExponent & 1UL) != 0UL)
-            {
-                result = result.MontgomeryMultiply(baseValue, modulus, nPrime);
-            }
+		// while (remainingExponent != 0UL)
+		// {
+		//     if ((remainingExponent & 1UL) != 0UL)
+		//     {
+		//         result = result.MontgomeryMultiply(baseValue, modulus, nPrime);
+		//     }
 
-            remainingExponent >>= 1;
-            if (remainingExponent == 0UL)
-            {
-                break;
-            }
+		//     remainingExponent >>= 1;
+		//     if (remainingExponent == 0UL)
+		//     {
+		//         break;
+		//     }
 
-            // Reusing baseValue to hold base^2 so we avoid allocating another register for the squared term.
-            baseValue = baseValue.MontgomeryMultiply(baseValue, modulus, nPrime);
-        }
+		//     // Reusing baseValue to hold base^2 so we avoid allocating another register for the squared term.
+		//     baseValue = baseValue.MontgomeryMultiply(baseValue, modulus, nPrime);
+		// }
 
-        remainders[index] = result.MontgomeryMultiply(1UL, modulus, nPrime);
+		// remainders[index] = result.MontgomeryMultiply(1UL, modulus, nPrime);
 
-        // Plain modular exponentiation without Montgomery reduction kept for reference.
-        // ulong plainResult = 1UL % modulus;
-        // ulong plainBase = 2UL % modulus;
-        // ulong plainExponent = exponent;
-        // while (plainExponent != 0UL)
-        // {
-        //     if ((plainExponent & 1UL) != 0UL)
-        //     {
-        //         plainResult = (plainResult * plainBase) % modulus;
-        //     }
-        //
-        //     plainExponent >>= 1;
-        //     if (plainExponent == 0UL)
-        //     {
-        //         break;
-        //     }
-        //
-        //     plainBase = (plainBase * plainBase) % modulus;
-        // }
-        // remainders[index] = plainResult;
+		// Plain modular exponentiation without Montgomery reduction kept for reference.
+		ulong plainResult = 1UL;// % modulus;
+		ulong plainBase = 2UL;// % modulus;
+		while (exponent != 0UL)
+		{
+			if ((exponent & 1UL) != 0UL)
+			{
+				plainResult = (plainResult * plainBase) % modulus;
+			}
+
+			exponent >>= 1;
+			if (exponent == 0UL)
+			{
+				break;
+			}
+
+			plainBase = (plainBase * plainBase) % modulus;
+		}
+		
+        remainders[index] = plainResult;
     }
 
     private static Action<AcceleratorStream, Index1D, ArrayView1D<GpuUInt128, Stride1D.Dense>, GpuUInt128, ArrayView1D<GpuUInt128, Stride1D.Dense>> GetPow2ModWideKernel(Accelerator accelerator)