From 886d59eecc33e4a96b247b3f729e607df351b416 Mon Sep 17 00:00:00 2001
From: John Halley Gotway <johnhg@ucar.edu>
Date: Mon, 14 Aug 2023 15:32:08 -0600
Subject: [PATCH] Per #2644, additional range checking to handle bad input
 values of t.

---
 src/basic/vx_math/ptile.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/basic/vx_math/ptile.cc b/src/basic/vx_math/ptile.cc
index b9b0d20da9..75b834f934 100644
--- a/src/basic/vx_math/ptile.cc
+++ b/src/basic/vx_math/ptile.cc
@@ -72,7 +72,7 @@ if ( n > 0 ) {
       p = ordered_array[index];
    }
    // Interpolate linearly between two values
-   else {
+   else if ( index >= 0 && index < (n - 1) ) {
       delta = (n - 1)*t - index;
       p = (1 - delta)*ordered_array[index] + delta*ordered_array[index + 1];
    }
@@ -119,7 +119,7 @@ if ( n > 0 ) {
       p = ordered_array[index];
    }
    // Interpolate linearly between two values
-   else {
+   else if ( index >= 0 && index < (n - 1) ) {
       delta = (n - 1)*t - index;
       p = (1 - delta)*ordered_array[index] + delta*ordered_array[index + 1];
    }