Re: Solving Equation with Ezunits Problem

Mateusz, thanks a lot for the bug report; I've pushed commit 6f96481 to fix it.

The example you gave is now in rtest_ezunits_mroz_examples.mac and the
result, with the current version of Maxima from Git, is:

foo2 : dimensionally(solve(expr, V_2))[1];
 => V_2 = -((300 ` Ohm*mA+3 ` kOhm*mA+(-20) ` V)/2)

rhs(foo2) `` V;
 => 167/20 ` V

as expected.

Thanks for your continued interest -- as I mentioned before I'm glad
to hear you find it useful.

Robert

On Mon, Jun 1, 2026 at 10:08 AM Mateusz M. <[email protected]> wrote:
>
> Hello everyone
>
> I ran into a strange issue related to solving equations using the ezunits package, and I was able to reproduce it with this very simple example:
>
> R_1: 1 `kOhm;
> R_2: 100 `Ohm;
> V_1: 10 `V;
> I: 3/2 `mA;
> expr: V_1 = (R_1 + R_2) * I + V_2;
>
>     (expr) 10 ` V=V_2+(3/2 ` mA)*(100 ` Ohm+1 ` kOhm)
>
> solve(expr, V_2)[1];
> rhs(%) ``V;
>
>     V_2=10 ` V+-(3/2) ` kOhm*mA+-150 ` Ohm*mA
>     167/20 ` V
>
> dimensionally(solve(expr, V_2))[1];
> rhs(%) ``V;
>
>      V_2=-(((300 ` Ohm+3 ` kOhm) ` mA+-20 ` V)/2)
>       (((-(300 ` Ohm)-3 ` kOhm)*A^2*s^3)/(2000*kg*m^2)+10) ` V
>
> It seems that "dimensionally" caused an error somehow. When the expression “(R_1 + R_2)” is replaced with simply “R_1”, the results match.
> This particular problem can be solved without using "dimensionally", but in most situations, that is not the case.
> Is this the expected behavior?
>
> Best regards,
> Mateusz Mróz
> _______________________________________________
> Maxima-discuss mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/maxima-discuss


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