Sage: Ticket #10311: solve()-ing Equations in CC
https://trac.sagemath.org/ticket/10311
<p>
The following looks like a bug to me, but feel free to correct me if I'm mistaken.
</p>
<pre class="wiki">sage: var('z')
sage: g1 = z^5 - (2 - I)*z^4 - (34 + 13*I)*z^3 + (22 - 51*I)*z^2 \
+ (53 - I)*z - 728 - 196*I == 0
sage:
sage: solve([g1], z)
[0 == z^5 + (I - 2)*z^4 - (13*I + 34)*z^3 - (51*I - 22)*z^2 -
(I - 53)*z - 196*I - 728]
sage:
sage: solve([g1, I == I], z)
[[z == (-4.00420663449 - 1.03443096055*I)], [z == (7.03872088238 +
1.11154206861*I)], [z == (1.40276621 - 2.70758376454*I)], [z == (
-3.78854832152 - 0.122376366114*I)], [z == (1.35126786363 +
1.7528490226*I)]]
sage:
sage: solve([g1, z == z], z)
[[z == (-4.00420663449 - 1.03443096055*I)], [z == (7.03872088238 +
1.11154206861*I)], [z == (1.40276621 - 2.70758376454*I)], [z == (
-3.78854832152 - 0.122376366114*I)], [z == (1.35126786363 +
1.7528490226*I)]]
</pre><p>
I think the problem is that <code>solve()</code> refuses to solve equation systems with more variables than equations, even if some of the variables are already known.
</p>
<p>
Regards<br />
Christoph
</p>
en-usSagehttps://trac.sagemath.org/chrome/site/logo_sagemath_trac.png
https://trac.sagemath.org/ticket/10311
Trac 1.1.6rbeezerMon, 07 Feb 2011 21:13:00 GMTowner, component changed
https://trac.sagemath.org/ticket/10311#comment:1
https://trac.sagemath.org/ticket/10311#comment:1
<ul>
<li><strong>owner</strong>
changed from <em>jason, was</em> to <em>burcin</em>
</li>
<li><strong>component</strong>
changed from <em>linear algebra</em> to <em>symbolics</em>
</li>
</ul>
<p>
Yes, that looks suspicious to me. I tried replacing all the instances of I in g1 by <code>imag=CC((0,1))</code>, with no better luck.
</p>
<p>
This is not really a linear algebra problem, but more of something to do with symbolics (where g1 lives) so I am going to change the component on this so it might get noticed sooner. If you haven't already, you might bring this up on sage-devel or sage-support - somebody might be able to confirm this as undesirable behavior, or offer a workaround.
</p>
TicketkcrismanTue, 13 Sep 2011 17:01:33 GMT
https://trac.sagemath.org/ticket/10311#comment:2
https://trac.sagemath.org/ticket/10311#comment:2
<p>
This <em>could</em> be related to <a class="needs_work ticket" href="https://trac.sagemath.org/ticket/10750" title="defect: Fix solve so that additional args are properly handled (needs_work)">#10750</a>.
</p>
TicketrwsWed, 15 Jul 2015 08:30:06 GMT
https://trac.sagemath.org/ticket/10311#comment:3
https://trac.sagemath.org/ticket/10311#comment:3
<p>
Should be addressed by <a class="new ticket" href="https://trac.sagemath.org/ticket/18900" title="enhancement: let solve delegate to roots (new)">#18900</a>.
</p>
Ticket