Halfway symbolic halfway numeric evaluation on wxMAXIMA

Hi Stavros:

Thanks for the suggestion - I was a long time MathCAD user who is so used
to it. So my work around is to create just a file for symbolics and another
for numeric.

Regards,
Berns B.


On Wed, Apr 17, 2013 at 5:41 PM, Stavros Macrakis <macrakis at alum.mit.edu>wrote:

> I believe this is the way wxMaxima is supposed to work. It has nothing to
> do specifically with symbolic vs numeric, but with its semantics of
> variable values. When you re- evaluate a cell, it uses current (dynamic)
> variable values, not the values in effect at the time the cell was created
> (textual or lexical order).  This can be very confusing, I agree. It also
> means that re evaluating a cell that refers to % will not refer to the
> textually preceding value, but the dynamically preceding value that was
> calculated.
>
> If you want to re evaluate from the top, I suggest you start with
> kill(all). If you want to re evaluate individual cells with their original
> context, I think you need to re evaluate all previous cells starting with
> kill (all). Or you might want to try other front ends to Maxima that have a
> different interaction model. Maybe batch files will work better for you,
> for example.
>
> Personally, I find the wxMaxima model confusing, but maybe I'm not using
> it as it was designed to be used.
>
>        -s
> On Apr 17, 2013 1:05 AM, "Berns Buenaobra" <berns.buenaobra at gmail.com>
> wrote:
>
>> Hello members:
>>
>> I have just recently adapted MAXIMA in my teaching for science education
>> and physics majors in class - the symbolic math is key and the biggest
>> motivator for students to have computer aided solution (to augment the
>> previous class training on long hand calculus and ODE etc.).
>>
>> It seemed that when I started using real values on the my sheet towards
>> the of end of my worksheet the earlier cells simply adapted and lost all my
>> symbols and computed numerically?  Is the effect of say having assigned a
>> value to a symbol say R:100, C:100e-6, L:35e-3 (from a problem in network
>> analysis) global?
>>
>> Will it be possible that I can selectively just on the same worksheet
>> enable symbolic on this cell and  that or from here to there?
>>
>> Thanks this is such a wonderful teaching tool for me.
>>
>> Regards,
>> Berns B.
>> USC Dept. of Physics (Cebu,Philippines)
>>
>>
>> On Wed, Apr 17, 2013 at 7:25 AM, <maxima-request at math.utexas.edu> wrote:
>>
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>>> than "Re: Contents of Maxima digest..."
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>>>
>>> Today's Topics:
>>>
>>>    1. Re: program works with maxima 5.29.1 but freezes  with    maxima
>>>       5.30.0 (Rupert Swarbrick)
>>>    2. Re: program works with maxima 5.29.1 but freezes  with    maxima
>>>       5.30.0 (Dmitry Shkirmanov)
>>>    3. Re: The wiki is back (Jaime Villate)
>>>    4. Re: DiracDelta (Richard Hennessy)
>>>    5. dependencies (Edwin Woollett)
>>>    6. Getting the coefficients of a polynomial (Stavros Macrakis)
>>>    7. Re: The wiki is back (Robert Dodier)
>>>    8. Re: Getting the coefficients of a polynomial (Richard Fateman)
>>>
>>>
>>> ----------------------------------------------------------------------
>>>
>>> Message: 1
>>> Date: Tue, 16 Apr 2013 18:34:18 +0100
>>> From: Rupert Swarbrick <rswarbrick at gmail.com>
>>> To: maxima at math.utexas.edu
>>> Subject: Re: [Maxima] program works with maxima 5.29.1 but freezes
>>>         with    maxima 5.30.0
>>> Message-ID: <qle04axqr7.ln2 at skate.rswarbrick>
>>> Content-Type: text/plain; charset="us-ascii"
>>>
>>> Dmitry Shkirmanov <piminusmeson at bk.ru> writes:
>>> > It seems that expand, not subst causes the problem. Does maxima show
>>> > you the expr1 in the end of the attached program? I cannot see it,
>>> > maxima consums all available memory and just hangs up.
>>>
>>> Well, I was running Maxima in a terminal / Emacs. I got a few pages of
>>> text before hitting Ctrl-C to interrupt the printing.
>>>
>>> The problem isn't expand though, I wouldn't think. It's almost certainly
>>> operating correctly. I expect that the problem is that what you are
>>> expanding is huge...
>>>
>>> Rupert
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>>>
>>> ------------------------------
>>>
>>> Message: 2
>>> Date: Tue, 16 Apr 2013 22:38:28 +0400
>>> From: Dmitry Shkirmanov <piminusmeson at bk.ru>
>>> To: maxima at math.utexas.edu
>>> Subject: Re: [Maxima] program works with maxima 5.29.1 but freezes
>>>         with    maxima 5.30.0
>>> Message-ID: <516D9AA4.80008 at bk.ru>
>>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>>
>>> >
>>> > The problem isn't expand though, I wouldn't think. It's almost
>>> certainly
>>> > operating correctly. I expect that the problem is that what you are
>>> > expanding is huge.
>>> >
>>> > My *guess* is that something simplified massively when you did the big
>>> > substitution on the previous version of Maxima
>>>
>>> It seems that you are right. "expand(factor(test2))"  returns good
>>> answer while  "expand(test2)"  consumes all available memory.  I just
>>> added the "factor" command manually. Now everything works as expected,
>>> so problem solved.
>>>
>>> Thank you very much for help.
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 3
>>> Date: Tue, 16 Apr 2013 20:14:07 +0100
>>> From: Jaime Villate <villate at fe.up.pt>
>>> To: maxima at math.utexas.edu
>>> Subject: Re: [Maxima] The wiki is back
>>> Message-ID: <516DA2FF.8040600 at fe.up.pt>
>>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>>
>>> If you access https://sourceforge.net/p/maxima/admin/wiki/permissions
>>> you can control who can do several different actions in the wiki: admin,
>>> configure, create, delete, edit, etc.
>>> I added "Developer" to almost all actions.
>>> You will notice that there is a group called "General", which is what I
>>> was planning to use; I have granted
>>> permission to create new wiki pages or edit the existing ones to the
>>> group General, which is currently empty.
>>>
>>> I have checked in https://sourceforge.net/p/maxima/admin/groups/ that by
>>> having granted those permissions in the wiki the general permissions for
>>> that Group have not changed, so I think that the wiki permissions will
>>> not interfere with git and other sections.
>>>
>>> We could then add users in the General group through
>>> https://sourceforge.net/p/maxima/admin/groups/
>>> Do you agree with this? Do you see any potential problems?
>>>
>>> Regards,
>>> Jaime
>>>
>>> On 04/16/2013 05:32 PM, Robert Dodier wrote:
>>> > On 2013-04-16, Jaime Villate <villate at fe.up.pt> wrote:
>>> >
>>> >> the new wiki, using the new Sourceforge software, is now active. It
>>> can
>>> >> be accessed from the homepage. The FAQ is now back in the Wiki.
>>> >> All developers with git access should also be able to modify the wiki
>>> >> (please do). Other people who would like to help us with the wiki,
>>> >> should be registered in Sourceforge and can  then send me a message
>>> >> telling me the sourceforge username and what they would like to help
>>> with.
>>> > Terrific. What is the procedure for a project administrator to grant
>>> > write permission to a non-developer? Is there a way to get a list of
>>> all
>>> > users who have write permission?
>>> >
>>> > best
>>> >
>>> > Robert Dodier
>>> >
>>> > _______________________________________________
>>> > Maxima mailing list
>>> > Maxima at math.utexas.edu
>>> > http://www.math.utexas.edu/mailman/listinfo/maxima
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 4
>>> Date: Tue, 16 Apr 2013 16:10:27 -0400
>>> From: "Richard Hennessy" <rich.hennessy at verizon.net>
>>> To: "Rupert Swarbrick" <rswarbrick at gmail.com>
>>> Cc: maxima at math.utexas.edu
>>> Subject: Re: [Maxima] DiracDelta
>>> Message-ID: <E48EDF6ADAFB40EC8B1149A86DE8E6FC at RichsLaptop>
>>> Content-Type: text/plain; charset="utf-8"
>>>
>>> On Apr 16, 2013 1:59 AM, "Richard Hennessy" <rich.hennessy at verizon.net>
>>> wrote:
>>> > Sorry if that confused anyone.  I am not just trying to solve
>>> integrate(pwdelta(x-a)*f(x),x) but also integrate(diff_pwdelta(i,x-a)
>>> *f(x),x).
>>>
>>> Ok but, to solve that, you can just use integration by parts, right?
>>> Since delta only picks up stuff at zero, you don't even have to worry about
>>> boundary values.
>>>
>>> Rupert
>>>
>>> Yes, integrate(du*v) = ?integrate(u*dv) because u*v = 0.
>>>
>>> Rich
>>>
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>>> >
>>>
>>> ------------------------------
>>>
>>> Message: 5
>>> Date: Tue, 16 Apr 2013 13:48:49 -0700
>>> From: "Edwin Woollett" <woollett at charter.net>
>>> To: "maxima mailing list" <maxima at math.utexas.edu>
>>> Subject: dependencies
>>> Message-ID: <60851BD48471466EB3CBDC377D6F7865 at edwinc367e16bd>
>>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>>>         reply-type=original
>>>
>>> The Maxima help manual states that
>>> dependencies is a list of atoms which have a
>>> functional dependence, assigned by depends or
>>> gradef.
>>>
>>> The help manual omits that dependencies is
>>> also a function:
>>>
>>> (%i1) dependencies;
>>> (%o1)                                 []
>>> (%i2) depends(u,t);
>>> (%o2)                               [u(t)]
>>> (%i3) dependencies;
>>> (%o3)                               [u(t)]
>>> (%i4) dependencies(a(t));
>>> (%o4)                               [a(t)]
>>> (%i5) dependencies;
>>> (%o5)                            [u(t), a(t)]
>>>
>>>
>>> Ted Woollett
>>>
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 6
>>> Date: Tue, 16 Apr 2013 17:40:26 -0400
>>> From: Stavros Macrakis <macrakis at alum.mit.edu>
>>> To: maxima mailing list <maxima at math.utexas.edu>
>>> Cc: ????? ??????? <akritas at uth.gr>
>>> Subject: Getting the coefficients of a polynomial
>>> Message-ID:
>>>         <
>>> CACLVabX-7bBGZVSTUwA59WqDQB9GqKXdddmtFPpQK3hyQr3imw at mail.gmail.com>
>>> Content-Type: text/plain; charset="iso-8859-1"
>>>
>>> How can I get the coefficients of a polynomial in x?
>>>
>>> Clearly I first put into into CRE form with main variable x:
>>>
>>>      poly: rat(input_poly,x)$
>>>
>>> Then what?  The internal form of the CRE lets you just "read off" the
>>> coefficients at this point, but I can't think of any Maxima function that
>>> lets you access that.
>>>
>>> I can loop like this:
>>>
>>>      coefs(p,v):=block([l:[]],while p # 0 do
>>> (l:cons(r:ratcoef(p,v,0),l),p:(p-r)/v),l)
>>>
>>> but that seems like an awful lot of work (*n* polynomial divisions).  It
>>> also isn't very efficient for sparse polynomials like x^20000.  You could
>>> do similar things with bothcoef or ratcoef, but again you end up
>>> building *n
>>> * intermediate polynomials as you remove terms.
>>>
>>> You might think you could use ratcoef for i:0..*n*, but how do you
>>> determine *n*?  hipow is inefficient in that it converts the expression
>>> into general representation first (!).
>>>
>>> Am I missing some obvious solution, or do we need to add rat_hipow and
>>> rat_coeffs or something?
>>>
>>>       rat_hipow(x^3+a*x+1,x) => 3
>>>       rat_coeffs(x^3+a*x+1,x) => [[3,1],[1,a],[0,1]]
>>>
>>> Edge cases to think about: CREs with negative powers, cf.
>>> ratcoef(1/x^3,x,-3) => 1, ratcoef(a/(b-x),x,-5) => -a*b^4, etc.
>>>
>>>            -s
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>>>
>>> ------------------------------
>>>
>>> Message: 7
>>> Date: Tue, 16 Apr 2013 22:53:38 +0000 (UTC)
>>> From: Robert Dodier <robert.dodier at gmail.com>
>>> To: maxima at math.utexas.edu
>>> Subject: Re: [Maxima] The wiki is back
>>> Message-ID: <kkkkpi$bcs$1 at ger.gmane.org>
>>>
>>> On 2013-04-16, Jaime Villate <villate at fe.up.pt> wrote:
>>>
>>> > Do you agree with this? Do you see any potential problems?
>>>
>>> OK by me.
>>>
>>> best
>>>
>>> Robert Dodier
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 8
>>> Date: Tue, 16 Apr 2013 16:25:00 -0700
>>> From: Richard Fateman <fateman at eecs.berkeley.edu>
>>> To: Stavros Macrakis <macrakis at alum.mit.edu>
>>> Cc: maxima mailing list <maxima at math.utexas.edu>, ????? ???????
>>>         <akritas at uth.gr>
>>> Subject: Re: [Maxima] Getting the coefficients of a polynomial
>>> Message-ID: <516DDDCC.5070909 at eecs.berkeley.edu>
>>> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>>>
>>> It seems to me that if you want to create an array of coefficients,
>>> there are a couple of things:
>>> sparse or dense?
>>>
>>> e.g.  is  5*x^4+1   supposed to be [5,0,0,0,1]   or [[5,4],[0,1]]?
>>>
>>>
>>> On 4/16/2013 2:40 PM, Stavros Macrakis wrote:
>>> > How can I get the coefficients of a polynomial in x?
>>> >
>>> > Clearly I first put into into CRE form with main variable x:
>>> >
>>> >      poly: rat(input_poly,x)$
>>> >
>>> > Then what?  The internal form of the CRE lets you just "read off" the
>>> > coefficients at this point, but I can't think of any Maxima function
>>> > that lets you access that.
>>> >
>>> > I can loop like this:
>>> >
>>> >      coefs(p,v):=block([l:[]],while p # 0 do
>>> > (l:cons(r:ratcoef(p,v,0),l),p:(p-r)/v),l)
>>>
>>> better would be somegthing like this  (no division, no re-ratting.)
>>>
>>>     coefs(p,v) := (p:rat(p,v), block([l:[]], while p#0 for i:hipow(p,v)
>>> step -1 thru 0 do(  l:cons(r:ratcoef(p,v,i), p:p-r*v^i))  , l));
>>>
>>> >
>>> > but that seems like an awful lot of work (/n/ polynomial divisions).
>>> >  It also isn't very efficient for sparse polynomials like x^20000.
>>> >  You could do similar things with bothcoef or ratcoef, but again you
>>> > end up building /n/ intermediate polynomials as you remove terms.
>>> >
>>> > You might think you could use ratcoef for i:0../n/, but how do you
>>> > determine /n/?  hipow is inefficient in that it converts the
>>> > expression into general representation first (!).
>>> >
>>> > Am I missing some obvious solution, or do we need to add rat_hipow and
>>> > rat_coeffs or something?
>>>
>>> rat_hipow(p,x):= ?cadadr(rat(p,x))
>>>
>>> >
>>> >       rat_hipow(x^3+a*x+1,x) => 3
>>> > rat_coeffs(x^3+a*x+1,x) => [[3,1],[1,a],[0,1]]
>>> >
>>> > Edge cases to think about: CREs with negative powers, cf.
>>> > ratcoef(1/x^3,x,-3) => 1, ratcoef(a/(b-x),x,-5) => -a*b^4, etc.
>>> >
>>> >            -s
>>> >
>>> >
>>> >
>>> > _______________________________________________
>>> > Maxima mailing list
>>> > Maxima at math.utexas.edu
>>> > http://www.math.utexas.edu/mailman/listinfo/maxima
>>>
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>>>
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>>>
>>
>>
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