From 98b3f414d44708b3afbbec1394eaf8d6e4debef2 Mon Sep 17 00:00:00 2001
From: Tony <tony@pyp-e.io>
Date: Mon, 27 Jan 2025 16:09:10 -0500
Subject: [PATCH] comment explaining the reason for use of Taus88

---
 fastRandom.cc | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fastRandom.cc b/fastRandom.cc
index 8e01c24..f9e2494 100644
--- a/fastRandom.cc
+++ b/fastRandom.cc
@@ -13,6 +13,14 @@ namespace Alepha::Hydrogen  ::detail::  fastRandom_m
 		struct FastRandomState
 		{
 			boost::random::taus88 fastRandomState{ std::random_device{}() };
+			/* The choice of Taus88 is deliberate.  The more familiar Mt19937
+			   is only slightly slower and its cousin Mt11213b is effectively
+			   no slower, but they require 100x to 200x as many integers to
+			   maintain state.  Thus with even only one random variable, the
+			   latter two will exceed cache line size and create cache load,
+			   but with several/many the cache pressure will be significant and
+			   affect performance not just for this code but for the system.
+			*/
 			std::uint32_t pool;
 			int remainingBits= 0;