commit 3f3efed3315f06ca3412bc8f4506e994ab84a8b3
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Sun Jun 16 10:14:02 2019 -0700
committer Mark Dickinson <dickinsm@gmail.com> Sun Jun 16 18:14:02 2019 +0100
tree 0021888d5c2a7e5c13ba7748dcb3f6b793ddefcc
parent 599f7ecb70f1b9714c702322b235b4d8155205ae

Turn math.isqrt assertion into a comment to clarify its purpose. (GH-14131)

(cherry picked from commit 2dfeaa9222e2ed6b6e32faaf08e5b0f77318f0a7)

Co-authored-by: Mark Dickinson <dickinsm@gmail.com>

Modules/mathmodule.c

diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 76d821c..82a9a14 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -1527,10 +1527,10 @@
         a = 1
         d = 0
         for s in reversed(range(c.bit_length())):
+            # Loop invariant: (a-1)**2 < (n >> 2*(c - d)) < (a+1)**2
             e = d
             d = c >> s
             a = (a << d - e - 1) + (n >> 2*c - e - d + 1) // a
-            assert (a-1)**2 < n >> 2*(c - d) < (a+1)**2
 
         return a - (a*a > n)