Sage: Ticket #21946: solve(x==x, x) returns [x == r1]
https://trac.sagemath.org/ticket/21946
<p>
Not sure if it's a bug or a problem with the documentation, but without any assumptions on <code>x</code>, <code>solve(x==x, x)</code> returns <code>[x == r1]</code>. The documentation does not state what <code>r1</code> is, but gives the following example:
</p>
<pre class="wiki"> If there is a parameter in the answer, that will show up as a new
variable. In the following example, "r1" is a real free variable
(because of the "r"):
sage: solve([x+y == 3, 2*x+2*y == 6],x,y)
[[x == -r1 + 3, y == r1]]
</pre><p>
However, without assumptions on <code>x</code>, there's no reason to believe that <code>x</code> is real.
</p>
<p>
This ticket also fixes a grammar issue introduced in <a class="closed ticket" href="https://trac.sagemath.org/ticket/21554" title="task: Document noninteger assumption in Maxima (closed: fixed)">#21554</a> (see comments).
</p>
en-usSagehttps://trac.sagemath.org/chrome/site/logo_sagemath_trac.png
https://trac.sagemath.org/ticket/21946
Trac 1.1.6aashu12Fri, 03 Mar 2017 04:04:36 GMTowner set
https://trac.sagemath.org/ticket/21946#comment:1
https://trac.sagemath.org/ticket/21946#comment:1
<ul>
<li><strong>owner</strong>
changed from <em>(none)</em> to <em>aashu12</em>
</li>
</ul>
Ticketaashu12Tue, 07 Mar 2017 21:54:51 GMTbranch set
https://trac.sagemath.org/ticket/21946#comment:2
https://trac.sagemath.org/ticket/21946#comment:2
<ul>
<li><strong>branch</strong>
set to <em>u/aashu12/documentation</em>
</li>
</ul>
Ticketaashu12Tue, 07 Mar 2017 21:59:12 GMTcommit, author set
https://trac.sagemath.org/ticket/21946#comment:3
https://trac.sagemath.org/ticket/21946#comment:3
<ul>
<li><strong>commit</strong>
set to <em>e8760d5ba490fa59a043879c2993b14c8ababde3</em>
</li>
<li><strong>author</strong>
set to <em>Ashutosh Ahelleya</em>
</li>
</ul>
<p>
New commits:
</p>
<table class="wiki">
<tr><td><a class="ext-link" href="https://git.sagemath.org/sage.git/commit?id=c7acfd690f5283e956bcce87f6a98668da21c798"><span class="icon"></span>c7acfd6</a></td><td><code>Fixes #21554</code>
</td></tr><tr><td><a class="ext-link" href="https://git.sagemath.org/sage.git/commit?id=e8760d5ba490fa59a043879c2993b14c8ababde3"><span class="icon"></span>e8760d5</a></td><td><code> Fixed: #21946</code>
</td></tr></table>
Ticketaashu12Tue, 07 Mar 2017 21:59:59 GMTstatus changed
https://trac.sagemath.org/ticket/21946#comment:4
https://trac.sagemath.org/ticket/21946#comment:4
<ul>
<li><strong>status</strong>
changed from <em>new</em> to <em>needs_review</em>
</li>
</ul>
TicketdimpaseFri, 10 Mar 2017 08:38:47 GMTdependencies set
https://trac.sagemath.org/ticket/21946#comment:5
https://trac.sagemath.org/ticket/21946#comment:5
<ul>
<li><strong>dependencies</strong>
set to <em>#21554</em>
</li>
</ul>
TicketdimpaseFri, 10 Mar 2017 09:07:29 GMTmilestone changed
https://trac.sagemath.org/ticket/21946#comment:6
https://trac.sagemath.org/ticket/21946#comment:6
<ul>
<li><strong>milestone</strong>
changed from <em>sage-7.5</em> to <em>sage-7.6</em>
</li>
</ul>
<p>
what do you mean to say by
</p>
<pre class="wiki">+ In case one of the solutions while solving an equation is a real number::
</pre><p>
First of all, I would have written
</p>
<pre class="wiki">+ In case one of the solutions of an equation is a real number::
</pre><p>
Still, it's unclear what the following sequence of assumptions following this line has
to do with the one of solutions being real. Do you mean to say that in order to make sure that one (rather, every?) solution is real, you need to make the following assumptions? Something else?
</p>
Ticketaashu12Fri, 10 Mar 2017 09:32:38 GMT
https://trac.sagemath.org/ticket/21946#comment:7
https://trac.sagemath.org/ticket/21946#comment:7
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/21946#comment:6" title="Comment 6">dimpase</a>:
</p>
<blockquote class="citation">
<p>
what do you mean to say by
</p>
<pre class="wiki">+ In case one of the solutions while solving an equation is a real number::
</pre><p>
First of all, I would have written
</p>
<pre class="wiki">+ In case one of the solutions of an equation is a real number::
</pre></blockquote>
<p>
It was a part of ticket <a class="closed ticket" href="https://trac.sagemath.org/ticket/21554" title="task: Document noninteger assumption in Maxima (closed: fixed)">#21554</a> which has already been merged.
</p>
<blockquote class="citation">
<p>
Still, it's unclear what the following sequence of assumptions following this line has
to do with the one of solutions being real. Do you mean to say that in order to make sure that one (rather, every?) solution is real, you need to make the following assumptions? Something else?
</p>
</blockquote>
<p>
According to the documentation provided earlier, the solution of the equation described in the issue is r1, which is a real number (That is what the documentation says!). But the solution to this equation can be a complex number too! So, I just changed the documentation and redefined r1 to be any arbitrary constant. You can refer to this conversation: <a class="ext-link" href="https://groups.google.com/forum/#!topic/sage-support/_XWjrYjk_3A"><span class="icon"></span>https://groups.google.com/forum/#!topic/sage-support/_XWjrYjk_3A</a>
</p>
TicketdimpaseFri, 10 Mar 2017 09:56:23 GMT
https://trac.sagemath.org/ticket/21946#comment:8
https://trac.sagemath.org/ticket/21946#comment:8
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/21946#comment:7" title="Comment 7">aashu12</a>:
</p>
<blockquote class="citation">
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/21946#comment:6" title="Comment 6">dimpase</a>:
</p>
<blockquote class="citation">
<p>
what do you mean to say by
</p>
<pre class="wiki">+ In case one of the solutions while solving an equation is a real number::
</pre><p>
First of all, I would have written
</p>
<pre class="wiki">+ In case one of the solutions of an equation is a real number::
</pre></blockquote>
<p>
It was a part of ticket <a class="closed ticket" href="https://trac.sagemath.org/ticket/21554" title="task: Document noninteger assumption in Maxima (closed: fixed)">#21554</a> which has already been merged.
</p>
</blockquote>
<p>
OK, I didn't notice this. But this makes no sense regardless, and you should fix it here.
</p>
<blockquote class="citation">
<blockquote class="citation">
<p>
Still, it's unclear what the following sequence of assumptions following this line has
to do with the one of solutions being real. Do you mean to say that in order to make sure that one (rather, every?) solution is real, you need to make the following assumptions? Something else?
</p>
</blockquote>
<p>
According to the documentation provided earlier, the solution of the equation described in the issue is r1, which is a real number (That is what the documentation says!).
But the solution to this equation can be a complex number too! So, I just changed the documentation and redefined r1 to be any arbitrary constant. You can refer to this conversation: <a class="ext-link" href="https://groups.google.com/forum/#!topic/sage-support/_XWjrYjk_3A"><span class="icon"></span>https://groups.google.com/forum/#!topic/sage-support/_XWjrYjk_3A</a>
</p>
</blockquote>
<p>
I understand this --- my question is wholly about the commit from <a class="closed ticket" href="https://trac.sagemath.org/ticket/21554" title="task: Document noninteger assumption in Maxima (closed: fixed)">#21554</a>.
How does this docstring clarify anything about assuming non-integer? I don't get it.
</p>
Ticketaashu12Fri, 10 Mar 2017 11:41:43 GMT
https://trac.sagemath.org/ticket/21946#comment:9
https://trac.sagemath.org/ticket/21946#comment:9
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/21946#comment:8" title="Comment 8">dimpase</a>:
</p>
<blockquote class="citation">
<p>
I understand this --- my question is wholly about the commit from <a class="closed ticket" href="https://trac.sagemath.org/ticket/21554" title="task: Document noninteger assumption in Maxima (closed: fixed)">#21554</a>.
How does this docstring clarify anything about assuming non-integer? I don't get it.
</p>
</blockquote>
<p>
No. The commits are different. I pushed them in different branches. But they showed up when I changed the author name.
That was what my doubt was about -> <a class="ext-link" href="https://groups.google.com/forum/#!topic/sage-support/iqqEhA4K2Gg"><span class="icon"></span>https://groups.google.com/forum/#!topic/sage-support/iqqEhA4K2Gg</a>
</p>
TicketdimpaseFri, 10 Mar 2017 11:52:17 GMT
https://trac.sagemath.org/ticket/21946#comment:10
https://trac.sagemath.org/ticket/21946#comment:10
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/21946#comment:9" title="Comment 9">aashu12</a>:
</p>
<blockquote class="citation">
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/21946#comment:8" title="Comment 8">dimpase</a>:
</p>
<blockquote class="citation">
<p>
I understand this --- my question is wholly about the commit from <a class="closed ticket" href="https://trac.sagemath.org/ticket/21554" title="task: Document noninteger assumption in Maxima (closed: fixed)">#21554</a>.
How does this docstring clarify anything about assuming non-integer? I don't get it.
</p>
</blockquote>
<p>
No. The commits are different. I pushed them in different branches. But they showed up when I changed the author name.
That was what my doubt was about -> <a class="ext-link" href="https://groups.google.com/forum/#!topic/sage-support/iqqEhA4K2Gg"><span class="icon"></span>https://groups.google.com/forum/#!topic/sage-support/iqqEhA4K2Gg</a>
</p>
</blockquote>
<p>
Differently named branches always have some common commits (and as I wrote on sage-support, it is the case that the commit c7acfd6 from <a class="closed ticket" href="https://trac.sagemath.org/ticket/21554" title="task: Document noninteger assumption in Maxima (closed: fixed)">#21554</a> is present in the branch here). Branch names are merely labels in the directed graph of commits in a repo.
</p>
<p>
Anyhow, c7acfd6 needs fixing, if only because it's broken English there...
</p>
Ticketaashu12Fri, 10 Mar 2017 11:55:20 GMT
https://trac.sagemath.org/ticket/21946#comment:11
https://trac.sagemath.org/ticket/21946#comment:11
<p>
Replying to <a class="ticket" href="https://trac.sagemath.org/ticket/21946#comment:10" title="Comment 10">dimpase</a>:
</p>
<blockquote class="citation">
<p>
Differently named branches always have some common commits (and as I wrote on sage-support, it is the case that the commit c7acfd6 from <a class="closed ticket" href="https://trac.sagemath.org/ticket/21554" title="task: Document noninteger assumption in Maxima (closed: fixed)">#21554</a> is present in the branch here). Branch names are merely labels in the directed graph of commits in a repo.
</p>
<p>
Anyhow, c7acfd6 needs fixing, if only because it's broken English there...
</p>
</blockquote>
<p>
Yea, I will fix it :)
</p>
TicketgitFri, 10 Mar 2017 13:04:57 GMTcommit changed
https://trac.sagemath.org/ticket/21946#comment:12
https://trac.sagemath.org/ticket/21946#comment:12
<ul>
<li><strong>commit</strong>
changed from <em>e8760d5ba490fa59a043879c2993b14c8ababde3</em> to <em>b88104716685c7864077452950ceee7280933b67</em>
</li>
</ul>
<p>
Branch pushed to git repo; I updated commit sha1. New commits:
</p>
<table class="wiki">
<tr><td><a class="ext-link" href="https://git.sagemath.org/sage.git/commit/?id=b88104716685c7864077452950ceee7280933b67"><span class="icon"></span>b881047</a></td><td><code> Fixed #21946</code>
</td></tr></table>
TicketgitFri, 10 Mar 2017 19:02:26 GMTcommit changed
https://trac.sagemath.org/ticket/21946#comment:13
https://trac.sagemath.org/ticket/21946#comment:13
<ul>
<li><strong>commit</strong>
changed from <em>b88104716685c7864077452950ceee7280933b67</em> to <em>ea063c358af8349cac165083099a381a29f5e922</em>
</li>
</ul>
<p>
Branch pushed to git repo; I updated commit sha1. New commits:
</p>
<table class="wiki">
<tr><td><a class="ext-link" href="https://git.sagemath.org/sage.git/commit/?id=ea063c358af8349cac165083099a381a29f5e922"><span class="icon"></span>ea063c3</a></td><td><code>Fixed #21946 and added example for #21554</code>
</td></tr></table>
Ticketgh-bryangingechenSat, 28 Jul 2018 10:27:03 GMTstatus changed
https://trac.sagemath.org/ticket/21946#comment:14
https://trac.sagemath.org/ticket/21946#comment:14
<ul>
<li><strong>status</strong>
changed from <em>needs_review</em> to <em>needs_work</em>
</li>
</ul>
<p>
This no longer merges.
</p>
Ticketgh-bryangingechenSat, 28 Jul 2018 15:07:48 GMTstatus, commit, description, branch changed
https://trac.sagemath.org/ticket/21946#comment:15
https://trac.sagemath.org/ticket/21946#comment:15
<ul>
<li><strong>status</strong>
changed from <em>needs_work</em> to <em>positive_review</em>
</li>
<li><strong>commit</strong>
changed from <em>ea063c358af8349cac165083099a381a29f5e922</em> to <em>224e0641f083472bda753ca8c1a833073b08a218</em>
</li>
<li><strong>description</strong>
modified (<a href="/ticket/21946?action=diff&version=15">diff</a>)
</li>
<li><strong>branch</strong>
changed from <em>u/aashu12/documentation</em> to <em>public/21946_solve_returns_r1</em>
</li>
</ul>
<p>
I fixed the merge conflict. Unless there are other outstanding objections, I'm setting this to positive_review as this is certainly an improvement to the docs.
</p>
<hr />
<p>
New commits:
</p>
<table class="wiki">
<tr><td><a class="ext-link" href="https://git.sagemath.org/sage.git/commit?id=e8760d5ba490fa59a043879c2993b14c8ababde3"><span class="icon"></span>e8760d5</a></td><td><code> Fixed: #21946</code>
</td></tr><tr><td><a class="ext-link" href="https://git.sagemath.org/sage.git/commit?id=b88104716685c7864077452950ceee7280933b67"><span class="icon"></span>b881047</a></td><td><code> Fixed #21946</code>
</td></tr><tr><td><a class="ext-link" href="https://git.sagemath.org/sage.git/commit?id=ea063c358af8349cac165083099a381a29f5e922"><span class="icon"></span>ea063c3</a></td><td><code>Fixed #21946 and added example for #21554</code>
</td></tr><tr><td><a class="ext-link" href="https://git.sagemath.org/sage.git/commit?id=224e0641f083472bda753ca8c1a833073b08a218"><span class="icon"></span>224e064</a></td><td><code>Merge branch 'u/aashu12/documentation' of git://trac.sagemath.org/sage into 21946_solve_returns_r1</code>
</td></tr></table>
Ticketgh-bryangingechenSat, 28 Jul 2018 15:12:37 GMTreviewer set
https://trac.sagemath.org/ticket/21946#comment:16
https://trac.sagemath.org/ticket/21946#comment:16
<ul>
<li><strong>reviewer</strong>
set to <em>Bryan Gin-ge Chen</em>
</li>
</ul>
TicketchapotonThu, 09 Aug 2018 15:28:26 GMTmilestone changed
https://trac.sagemath.org/ticket/21946#comment:17
https://trac.sagemath.org/ticket/21946#comment:17
<ul>
<li><strong>milestone</strong>
changed from <em>sage-7.6</em> to <em>sage-8.4</em>
</li>
</ul>
TicketvbraunSat, 11 Aug 2018 16:55:13 GMTstatus, branch changed; resolution set
https://trac.sagemath.org/ticket/21946#comment:18
https://trac.sagemath.org/ticket/21946#comment:18
<ul>
<li><strong>status</strong>
changed from <em>positive_review</em> to <em>closed</em>
</li>
<li><strong>resolution</strong>
set to <em>fixed</em>
</li>
<li><strong>branch</strong>
changed from <em>public/21946_solve_returns_r1</em> to <em>224e0641f083472bda753ca8c1a833073b08a218</em>
</li>
</ul>
Ticket