normalization in Pynac buggy

[rwst]

from https://groups.google.com/forum/?hl=en#!topic/sage-devel/awa0lNGJugo
Minimal version:

sage: a,b,c,d,e=var('a,b,c,d,e')
sage: (c/a - b*c^2/(a^2*(b*c/a-d)) + c*d/(a*(b*c/a-d))).normalize()
0
sage: (e + c/a - b*c^2/(a^2*(b*c/a-d)) + c*d/(a*(b*c/a-d))).normalize()
(a^2*b*c*e - a^3*d*e)/((b*c - a*d)*a^2)

This changed somewhere between 6.6 (output e) and 7.0.

See pynac/pynac#111

Depends on #21034

Upstream: Fixed upstream, in a later stable release.

Component: symbolics

Author: Ralf Stephan

Reviewer: Paul Masson

Issue created by migration from https://trac.sagemath.org/ticket/19775

[rwst]

Upstream: Reported upstream. Developers acknowledge bug.

[rwst]

Description changed:

--- 
+++ 
@@ -10,4 +10,4 @@
 sage: (e + c/a - b*c^2/(a^2*(b*c/a-d)) + c*d/(a*(b*c/a-d))).normalize()
 (a^2*b*c*e - a^3*d*e)/((b*c - a*d)*a^2)
 ```
-
+See https://github.com/pynac/pynac/issues/111

[rwst]

Description changed:

--- 
+++ 
@@ -1,13 +1,13 @@
 from https://groups.google.com/forum/?hl=en#!topic/sage-devel/awa0lNGJugo
+Minimal version:
 
 ```
-sage: a,b,c,d,e=var('a,b,c,d,e')
-sage: (e + c/a - b*c^2/(a^2*(b*c/a-d)) + c*d/(a*(b*c/a-d))).numerator()
-a^2*b*c*e - a^3*d*e
-sage: (c/a - b*c^2/(a^2*(b*c/a-d)) + c*d/(a*(b*c/a-d))).numerator()
-0
+sage: a,b=var('a,b')
+sage: (a*b+b)/(a+1)
+(a*b + b)/(a + 1)
+sage: (a*2+2)/(a+1)
+2
+```
+This changed somewhere between 6.6 and 7.0.
 
-sage: (e + c/a - b*c^2/(a^2*(b*c/a-d)) + c*d/(a*(b*c/a-d))).normalize()
-(a^2*b*c*e - a^3*d*e)/((b*c - a*d)*a^2)
-```
 See https://github.com/pynac/pynac/issues/111

[rwst]

Description changed:

--- 
+++ 
@@ -2,12 +2,12 @@
 Minimal version:
 
 ```
-sage: a,b=var('a,b')
-sage: (a*b+b)/(a+1)
-(a*b + b)/(a + 1)
-sage: (a*2+2)/(a+1)
-2
+sage: a,b,c,d,e=var('a,b,c,d,e')
+sage: (c/a - b*c^2/(a^2*(b*c/a-d)) + c*d/(a*(b*c/a-d))).normalize()
+0
+sage: (e + c/a - b*c^2/(a^2*(b*c/a-d)) + c*d/(a*(b*c/a-d))).normalize()
+(a^2*b*c*e - a^3*d*e)/((b*c - a*d)*a^2)
 ```
-This changed somewhere between 6.6 and 7.0.
+This changed somewhere between 6.6 (output `e`) and 7.0.
 
 See https://github.com/pynac/pynac/issues/111

[rwst]

comment:4

Fixed in pynac-0.6.8.

[rwst]

Changed upstream from Reported upstream. Developers acknowledge bug. to Fixed upstream, in a later stable release.

[paulmasson]

Dependencies: #21034

[paulmasson]

Reviewer: Paul Masson