matrix inversion broken with doallmxops:false

[rtoy]

Imported from SourceForge on 2024-07-03 11:27:39 Created by macrakis on 2020-12-18 17:36:07 Original: https://sourceforge.net/p/maxima/bugs/3690

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M: matrix([1,2],[3,4]) doscmxops => true (check default) M^^-1 => matrix([-2,1],[3/2,-1/2]) OK M^^2 => matrix([7,10],[15,22]) OK

but

doallmxops:false$ M^^-1 => ERROR not a matrix: -matrix([4,-2],[-3,1])/2

I believe this is a bug in two ways:

• The doXXXops flags are only supposed to control whether the operation is carried through, and shouldn't cause errors.
• M^^2 isn't controlled by doallmxops; why is ^^-1?

Apparently, internally, it's depending on doallmxops being true.

Maxima 5.44.0, SBCL 2.0.0, Windows 10

[rtoy]

Imported from SourceForge on 2024-07-03 11:27:40 Created by macrakis on 2020-12-18 17:44:43 Original: https://sourceforge.net/p/maxima/bugs/3690/#cbfd

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• Description has changed:

Diff:

--- old
+++ new
@@ -14,3 +14,5 @@
 * M^^2 isn't controlled by **doallmxops**; why is ^^-1?

 Apparently, internally, it's depending on doallmxops being true.
+
+Maxima 5.44.0, SBCL 2.0.0, Windows 10