[Maxima-bugs] [ maxima-Bugs-3510152 ] Cannot solve siultaneous equations

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Bugs item #3510152, was opened at 2012-03-22 09:49
Message generated for change (Comment added) made by rtoy
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Category: Lisp Core - Solving equations
Group: None
>Status: Pending
>Resolution: Invalid
Priority: 5
Private: No
Submitted By: Rigoberto Gómez Cruz (rgomezor)
Assigned to: Nobody/Anonymous (nobody)
Summary: Cannot solve siultaneous equations

Initial Comment:
In trying to solve this system,
/* [wxMaxima: input   start ] */
debugmode(true);
debugger-hook(nil);
coef: matrix ([1, log(2e-3), log(1.5e-3), log(1e0)], [1, log(4e-3), log(1.5e-3), log(1e0)], [1, log(4e-3), log(3e-3), log(2e0)], [1, log(4e-3), log(3e-3), log(1e0)]);
v: matrix ([log(1.8e-4)], [log(3.6e-4)], [log(1.8e-4)], [log(7.2e-4)]);
v / coef;
/* [wxMaxima: input   end   ] */

One gets this message
Maxima encountered a Lisp error:
 Error in FMAPL1 [or a callee]: Caught fatal error [memory may be damaged]
Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.

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>Comment By: Raymond Toy (rtoy)
Date: 2012-03-22 10:24

Message:
Not sure why you think  v / coef will solve a linear system for you.  It
doesn't.  It's trying to take the reciprocal of each element of coef, which
contains a 0.

You might want to try linsolve_by_lu(coef, v, 'floatfield).

Marking as pending/invalid.

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You can respond by visiting: 
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