From: Taylor R Campbell <campbell@mumble.net>
Date: Thu, 25 Oct 2018 05:21:46 +0000 (+0000)
Subject: Clarify justification for ditching the denominator.
X-Git-Tag: mit-scheme-pucked-10.1.2~16^2~164
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=09d810ca0d68746ad1bbd525a8f4e93ed747794f;p=mit-scheme.git

Clarify justification for ditching the denominator.
---

diff --git a/src/runtime/arith.scm b/src/runtime/arith.scm
index 60459c49e..2eb29f578 100644
--- a/src/runtime/arith.scm
+++ b/src/runtime/arith.scm
@@ -2232,7 +2232,7 @@ USA.
   (guarantee-real t 'logit-exp)
   (cond ((<= t -37)
          ;; e^t < eps/2, so since log(e^t/(1 - e^t)) = t - log(1 -
-         ;; e^t), we have
+         ;; e^t), and |log(1 - e^t)| < 1 < |t|, we have
          ;;
          ;;     |t - log(e^t/(1 - e^t))|/|log(e^t/(1 - e^t))|
          ;;      = |log(1 - e^t)|/|t - log(1 - e^t)|.