From: Taylor R Campbell <campbell@mumble.net>
Date: Wed, 31 Oct 2018 16:44:43 +0000 (+0000)
Subject: Comment what log-logistic and logit-exp are for.
X-Git-Tag: mit-scheme-pucked-10.1.2~16^2~127
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=861d47756fc5555408ef13855e0201e14092b56a;p=mit-scheme.git

Comment what log-logistic and logit-exp are for.
---

diff --git a/src/runtime/arith.scm b/src/runtime/arith.scm
index 0adb24ef5..edf7ca3fe 100644
--- a/src/runtime/arith.scm
+++ b/src/runtime/arith.scm
@@ -2408,6 +2408,8 @@ USA.
 	 (log (/ (+ 1/2 p-1/2) (- 1/2 p-1/2))))))
 
 ;;; log logistic(x) = log (1/(1 + e^{-x})) = -log (1 + e^{-x})
+;;;
+;;; This is the log density of the logistic distribution.
 
 (define (log-logistic x)
   (guarantee-real x 'log-logistic)
@@ -2419,6 +2421,8 @@ USA.
   (flo:- 0. (flo:log (flo:+ 1. (flo:exp -1.)))))
 
 ;;; logit(e^t) = log e^t/(1 - e^t)
+;;;
+;;; Inverse of log logistic.
 
 (define (logit-exp t)
   (guarantee-real t 'logit-exp)