I've took a look a the example code, and so I think that the bug is
in the dumps and load function:
var('Rs')
mio = Rs + Rs*Rs + sqrt(10)
tuo=loads(dumps(mio))
print mio._operands[0]._operands[0] is Rs
print tuo._operands[0]._operands[0] is Rs
IAt this time I've not looked inside the code, but I think that it
will be simple for the developer of
this functions to find the solution! :)
If there is not an intrepid volunteer I will look at that on
Saturday...
On Feb 27, 9:51 am, Maurizio <maurizio.gran...@gmail.com> wrote:
> Carl,
> you were totally right.
>
> The results are matching your previsions. I get:
> var('Cb')
> G_igr_d._operands[1]._operands[1] is Cb
>
> False
>
> G_works = SR(repr(G_igr_d))
> time G_works.subs(paramsd)
>
> Time: CPU 0.16 s, Wall: 0.86 s
>
> I add now another aspect: the G_igr_d is symbolically evaluated in
> another worksheet, then I save it, and I load it back in the "numeric"
> worksheet, where I do all the numerical maths.
>
> If I go to the "symbolic" worksheet, I get:
>
> G_igr_d._operands[1]._operands[1] is Cb
> True
>
> What does this mean?
> Please note that in the symbolic worksheet, the Cb is declared only
> once (on top) as:
> var('Cb rCb Cf rCf Lf rLf Rs rQ')
>
> in the same way it is done in the numeric worksheet:
> var('rQ rCb rLf rCf Duty')
> var('Cb Lf Cf')
>
> What am I missing? I don't seem to catch any particular interaction
> with other symbolic system. The functions I use are:
> solve and subs, symplify and expand, matrix operations ( + * **(-1) ),
> matrix augmentation (augment), and then matrix extraction of elements
> (by column and row index)
>
> Any other info is needed? Hopefully this can fix an undiscovered bug,
> or at least fix my mistake (which maybe can be helpful as well to the
> community!)
>
> Maurizio
>
> On 27 Feb, 02:58, Carl Witty <carl.wi...@gmail.com> wrote:
>
> > On Wed, Feb 25, 2009 at 2:33 PM, Maurizio <maurizio.gran...@gmail.com>
> > wrote:
> > > Is it a problem interfacing to any symbolic package different from the
> > > ordinary maxima one? I don't exactly recall if I took advantage of
> > > others.
>
> > OK, I spent some time looking at this, and this may indeed be the
> > problem. I have a workaround for your case, but I may need more
> > information to get somebody to actually fix the problem.
>
> > Can you try this test:
>
> > var('Cb')
> > G_igr_d._operands[1]._operands[1] is Cb
>
> > and report what the last line prints?
>
> > If it prints False, then you're seeing what I'm seeing: somehow you
> > have two different synbolic variable objects, both named Cb.
> > Ordinarily you would only ever have one such object. With two
> > separate objects, Python can't immediately answer the question whether
> > Cb_1==Cb_2, so it asks Maxima (which says yes, they're equal).
>
> > In that case, the workaround is to do:
> > G_works = SR(repr(G_igr_d))
> > This is an ugly hack that prints out G_igr_d, and then parses it back
> > in; doing so makes it use the standard variable objects.
>
> > If this is the problem, can you try to remember how you actually got
> > G_igr_d? It seems like the problem actually might be the integration
> > with some other symbolic system, and it would be very helpful to know
> > which one.
>
> > Carl
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