Error in comparing two Symbolic Ring elements

[yuan-zhou]

It seems a bug:

sage: bool(AA(sqrt(2))/pi == sqrt(2)/pi)
TypeError: ECL says: THROW: The catch MACSYMA-QUIT is undefined.

The following comparison is fine, though.

sage: bool(AA(sqrt(2)) == sqrt(2))
True

To fix this, we provide elements of AA and QQbar with a _maxima_init_ method that

• handles the case of elements for which Sage can find a radical expression and
• raises an error in all other cases. This is better than sending the unusable print representation of algebraic numbers (including ?) to Maxima.

CC: @mkoeppe @DaveWitteMorris @videlec @tscrim

Component: symbolics

Author: Matthias Koeppe

Branch/Commit: 58f4cd1

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/34235

[mkoeppe]

comment:2

Confirmed in 9.7.beta5

[mkoeppe]

Branch: u/mkoeppe/error_in_comparing_two_symbolic_ring_elements

[mkoeppe]

Description changed:

--- 
+++ 
@@ -10,3 +10,6 @@
 sage: bool(AA(sqrt(2)) == sqrt(2))
 True

+ +To fix this, we provide elements of AA and QQbar with a _maxima_init_ method that handles the easiest cases (rationals, square roots of rationals) and raises an error in all other cases. This is better than sending the unusable print representation of algebraic numbers (including ?) to Maxima. +

[mkoeppe]

New commits:

a627ce6

src/sage/rings/qqbar.py (AlgebraicNumber_base._maxima_init_): New

[mkoeppe]

Commit: a627ce6

[mkoeppe]

Author: Matthias Koeppe

[7ed8c4ca-6d56-4ae9-953a-41e42b4ed313]

Changed commit from a627ce6 to 6204a76

[7ed8c4ca-6d56-4ae9-953a-41e42b4ed313]

Branch pushed to git repo; I updated commit sha1. New commits:

6204a76

src/sage/rings/qqbar.py (AlgebraicNumber_base._maxima_init_): Fixup

[7ed8c4ca-6d56-4ae9-953a-41e42b4ed313]

Changed commit from 6204a76 to 3e560cf

[7ed8c4ca-6d56-4ae9-953a-41e42b4ed313]

Branch pushed to git repo; I updated commit sha1. New commits:

3e560cf

src/sage/rings/qqbar.py: Add doctest

[mkoeppe]

comment:7

Instead of defining _maxima_init_, perhaps it's better to define _symbolic_

[7ed8c4ca-6d56-4ae9-953a-41e42b4ed313]

Branch pushed to git repo; I updated commit sha1. New commits:

58f4cd1

src/sage/rings/qqbar.py (AlgebraicNumber_base._maxima_init_): Generalize using radical_expression

[7ed8c4ca-6d56-4ae9-953a-41e42b4ed313]

Changed commit from 3e560cf to 58f4cd1

[mkoeppe]

Description changed:

--- 
+++ 
@@ -11,5 +11,5 @@
 True

-To fix this, we provide elements of AA and QQbar with a _maxima_init_ method that handles the easiest cases (rationals, square roots of rationals) and raises an error in all other cases. This is better than sending the unusable print representation of algebraic numbers (including ?) to Maxima. +To fix this, we provide elements of AA and QQbar with a _maxima_init_ method that handles the case of elements for which Sage can find a radical expression and raises an error in all other cases. This is better than sending the unusable print representation of algebraic numbers (including ?) to Maxima.

[mkoeppe]

Description changed:

--- 
+++ 
@@ -11,5 +11,8 @@
 True

-To fix this, we provide elements of AA and QQbar with a _maxima_init_ method that handles the case of elements for which Sage can find a radical expression and raises an error in all other cases. This is better than sending the unusable print representation of algebraic numbers (including ?) to Maxima. +To fix this, we provide elements of AA and QQbar with a _maxima_init_ method that +- handles the case of elements for which Sage can find a radical expression and +- raises an error in all other cases. +This is better than sending the unusable print representation of algebraic numbers (including ?) to Maxima.

[tscrim]

comment:13

LGTM.

[tscrim]

Reviewer: Travis Scrimshaw

[mkoeppe]

comment:14

Thanks!

[vbraun]

Changed branch from u/mkoeppe/error_in_comparing_two_symbolic_ring_elements to 58f4cd1