From 26ea755cad30f6959cff6248dea62550764938fe Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 1 Sep 2026 07:07:39 +0000
Subject: [PATCH 1/2] Fix rescale() silent divide-by-zero on
 constant/single-element input

rescale(vec, from, upto) computed vec - min(vec), then divided by
max(vec) of that shifted vector. For a constant vector (or any
single-element vector), the shifted vector is all zeros, so max(vec)
is 0, and dividing by it silently produces Inf/NaN for every element
instead of an error or a meaningful value - no warning is raised.

Fix: detect the zero-range case (max == min) up front and return the
midpoint of the target range, (from + upto) / 2, for all non-NA
elements instead. This matches the well-established convention used
by scales::rescale() for the identical degenerate-input case
(verified: scales::rescale(c(5,5,5), to = c(0,100)) returns
c(50,50,50)) - using an existing, widely-used package's behavior as
the precedent avoids guessing a novel convention for this edge case.

Verified: normal (non-degenerate) input is unaffected; constant
vectors and single-element vectors now return the range midpoint
instead of all-NaN; NA elements are left as NA rather than being
assigned the midpoint; a custom target range on constant input
scales correctly too.

Version bumped 2.8.16 -> 2.8.20 (distinct from sibling PRs #75/#76/#77,
which also branch from the same 2.8.16 base and already claimed
2.8.17/2.8.18/2.8.19).
---
 DESCRIPTION          |  2 +-
 Development/config.R |  2 +-
 R/CodeAndRoll2.R     | 10 ++++++++--
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 227f9ee..444ef2d 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: CodeAndRoll2
 Title: CodeAndRoll2 for vector, matrix and list manipulations
-Version: 2.8.16
+Version: 2.8.20
 Authors@R: 
     person("Abel", "Vertesy", , "av@imba.oeaw.ac.at", role = c("aut", "cre"))
 Description: CodeAndRoll2 is a set of more than 170 productivity functions
diff --git a/Development/config.R b/Development/config.R
index cc4bdcb..8b1745c 100644
--- a/Development/config.R
+++ b/Development/config.R
@@ -3,7 +3,7 @@
 
 DESCRIPTION <- list(
   package.name = "CodeAndRoll2",
-  version = "2.8.16",
+  version = "2.8.20",
   title = "CodeAndRoll2 for vector, matrix and list manipulations",
   description = "CodeAndRoll2 is a set of more than 170 productivity functions for vector, matrix
   and list manipulations and math. Used by MarkdownReports, ggExpress, SeuratUtils, etc.",
diff --git a/R/CodeAndRoll2.R b/R/CodeAndRoll2.R
index efafc51..05bc70d 100644
--- a/R/CodeAndRoll2.R
+++ b/R/CodeAndRoll2.R
@@ -1273,8 +1273,14 @@ translate <- function(vec, old, new) {
 #' @param upto max, Default: 100
 #' @export
 rescale <- function(vec, from = 0, upto = 100) {
-  vec <- vec - min(vec, na.rm = TRUE)
-  vec <- vec * ((upto - from) / max(vec, na.rm = TRUE))
+  vmin <- min(vec, na.rm = TRUE)
+  vmax <- max(vec, na.rm = TRUE)
+  if (vmax == vmin) {
+    vec[!is.na(vec)] <- (from + upto) / 2
+    return(vec)
+  }
+  vec <- vec - vmin
+  vec <- vec * ((upto - from) / (vmax - vmin))
   vec <- vec + from
   return(vec)
 } # fun

From e386a56546c95810b92e566c8992068e551ecdca Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 1 Sep 2026 07:12:03 +0000
Subject: [PATCH 2/2] Fix overflow in rescale()'s constant-input midpoint
 calculation

The constant-input branch computed (from + upto) / 2, which can
overflow to Inf before the division when from and upto are both
large finite numbers (e.g. from = 1e308, upto = 1.1e308 - their sum
exceeds .Machine$double.xmax, so the "midpoint" was Inf instead of
the correct finite 1.05e308).

Fix: compute the midpoint as from + (upto - from) / 2 instead -
the subtraction of two same-magnitude numbers doesn't overflow, and
adding a bounded increment to from doesn't either.

Verified: the flagged overflow case now returns the correct finite
midpoint (1.05e+308) instead of Inf; normal constant-input and
non-degenerate cases are unchanged.
---
 R/CodeAndRoll2.R | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/CodeAndRoll2.R b/R/CodeAndRoll2.R
index 05bc70d..599dcf7 100644
--- a/R/CodeAndRoll2.R
+++ b/R/CodeAndRoll2.R
@@ -1276,7 +1276,7 @@ rescale <- function(vec, from = 0, upto = 100) {
   vmin <- min(vec, na.rm = TRUE)
   vmax <- max(vec, na.rm = TRUE)
   if (vmax == vmin) {
-    vec[!is.na(vec)] <- (from + upto) / 2
+    vec[!is.na(vec)] <- from + (upto - from) / 2
     return(vec)
   }
   vec <- vec - vmin