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Re: WolframAlpha[] give results but not parse!

  • To: mathgroup at smc.vnet.net
  • Subject: [mg114559] Re: WolframAlpha[] give results but not parse!
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Tue, 7 Dec 2010 06:49:36 -0500 (EST)

But

   WolframAlpha["solve dy/dt=2y(1-y)", "MathematicaForms"]

only gives Mathematica syntax for the _result_ of the DSolve command, 
still not the input.

If the WolframAlpha server is parsing my input sufficiently to 
understand and evaluate it, why is it not returning, also, the 
corresponding Mathematica DSolve input?


On 12/6/2010 6:13 AM, Maxim wrote:
> On Dec 4, 5:15 am, Murray Eisenberg<mur... at math.umass.edu>  wrote:
>> In Mathematica 8.0, the following gives the expected explicit
>> solution, graphs, etc.:
>>
>>    WolframAlpha["solve dy/dt=2y(1-y)"]
>>
>> It even tells me the interpretation as "solve y'(t)=2y(1-y)".  Of
>> course, just using input
>>
>>    =solve dy/dt=2y(1-y)
>>
>> gives the same results.
>>
>> However, the following (as well as the Ctrl= input form for it) gives
>> no Mathematica translation of the input:
>>
>>    WolframAlpha["solve dy/dt=2y(y-1)","MathematicaParse"]
>>
>> It is surprising that WolframAlpha "understands" what I asked but
>> cannot actually tell me in Mathematica syntax the same thing!
>>
>> Or am I missing something?
>>
>> --
>>    Murray Eisenberg                       Internet:  mur... at math.umass.edu
>>    Mathematics&  Statistics Dept.            Voice:  413-545-2859 (W)
>>    University of Massachusetts                     413-549-1020 (H)
>>    Amherst, MA 01003                          Fax:  413-545-1801
>
> This is a bit of an implementation detail, but (simplifying things
> somewhat) the query goes through the W|A parser first and sometimes
> the result of the parse is an expression that can be evaluated on its
> own on the client side. In that case you get "MathematicaParse". Other
> times the result of the parse is an intermediate form which invokes W|
> A scanners. The scanners generate the pods and the pods can contain
> "Mathematica plaintext output" fields. You can extract those by doing
> WolframAlpha["solve dy/dt=2y(1-y)", "MathematicaForms"].
>
> Maxim Rytin
> m.r at inbox.ru
>

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305


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