From ac1a8b70398842c8aa6b54246873d08aff1ba497 Mon Sep 17 00:00:00 2001
From: datalore <d4t4.l0r3@protonmail.ch>
Date: Thu, 3 Oct 2024 01:13:34 +0200
Subject: [PATCH] change(generatePrimesCPU): Now aborting at half of candidate

Numbers larger than the half of a number are not able to divide a number
---
 main.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/main.go b/main.go
index 58f4999..4bb4cf8 100644
--- a/main.go
+++ b/main.go
@@ -33,12 +33,18 @@ func printProgress(progress <-chan float32, message string) {
 }
 
 func checkIsDivisibleByPrime(number int64, offset, stride int, primes *[]int64, resultChannel chan bool, ctx context.Context) {
+	threshold := number / 2
 	for i := offset; i < len(*primes); i += stride {
 		select {
 			case <-ctx.Done():
 				resultChannel <- false
 				return
 			default:
+				// no need to continue checking if number is greater than half our number, division is already impossible
+				if (*primes)[i] > threshold {
+					resultChannel <- false
+					return
+				}
 				// only have to check primes, because all other numbers are multiple of primes.
 				// if a number is divisible by a multiple of a prime, it is by definition also divisible by the prime itself.
 				if number % (*primes)[i] == 0 {