ecterrab

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These are Posts that have been published by ecterrab

Hi
In connection with recent developments in the Physics package, we now have mathematical typesetting for all the inert functions of the mathematical language. Hey! This is within the Physics update available on the Maplesoft Physics: Research & Development webpage

I think this is an interesting development that will concretely change the computational experience with these functions: it is not the same to compute with something you see displayed as %exp(x) instead of the same computation but flowing with it nicely displayed as an exponential function with the e in grey, reflecting that Maple understands this object as the exponential inert function, with known properties (all those of the active exp function), and so Maple can compute with the inert one taking these properties into account while not executing the function itself - and this is the essence of the inert function behaviour.

Introducing mathematical display, copy and paste for all these inert functions of the mathematical language concretely increases the mathematical expressiveness of the system, for teaching, working and also for presenting ideas.

Attached is a brief illustration.

Edgardo S. Cheb-Terrab
Physics, Maplesoft

InertMathematicalFun.mw  InertMathematicalFun.pdf

Hi
Just finished updating the comparison between Maple 17.02 and Mathematica 9.01 in solving the 1390 Ordinary Differential Equations (ODEs) of Kamke's book:

  • Mathematica solved 80% in 7 hours and 8 minutes
     
  • Maple solved 97.5% in 43 minutes

While trying to solve the whole set, Mathematica hanged with 90 of these ODEs while Maple hanged with 6 ODEs. A pdf with a summarizing table and all the details is linked below

It is also relevant here that Maple's dsolve has close to half of its code implementing more modern methods, not found in Kamke, illustrated in the Maple 'what's new in DEs' help pages of the last 10 releases; for these other kinds of equations the difference is more impressive. I'll see to prepare another post about that.

Edgardo S. Cheb-Terrab
Physics, Maplesoft

Comparison_Kamke.pdf

Hi

It's been 1 and 1/2 months since updates for the Maple Physics package have been distributed in the Maplesoft webpage "Maple Physics: Research & Development".  The number of Mapleprimes Physics posts that got rapidly addressed in this way is already large, some of them are listed here.

The experience has been great. Suggestions are implemented and problems are fixed in a couple of days since they were posted here, and the changes are made available to everybody right away. This is moving the focus of developments into the topics people are actually working on, with feedback and related downloadable updates happening every week.

The recent Physics updates are mostly related to quantum mechanics, an advanced topic, but part of the resulting functionality is interesting for algebraic computations in general. To mention but one: the "automatic combination of products of powers of same base" is now optional.

Recalling, by default, in Maple, if you enter xn xm, in order to receive x(n+m). you need to use the combine command (the same happens with products of exponentials). The idea behind the Maple approach is to give you more control over the steps. On the other hand, depending on your problem, the automatic combination of powers of the same base is a desired automatic simplification - this is for instance the Mathematica approach.

In today's update of Physics, a new Setup option, 'combinepowersofsamebase', is implemented, so that this automatic simplification is now optional. If set to true (> Setup(combine = true))you enter xn xm or exp(A) exp(B) and you respectively receive x(n+m) and exp(A+B). Being able to turn this automatic simplification ON and OFF comes in handy in varied situations.

Those more familiar with noncommutative objects (e.g. Matrices), also know that the combination of exp(A) exp(B) is not valid when the exponents A and B do not commute, unless A and B commute with their commutator AB - BA, in which case the combination can be done using Glauber's formula (also related to Hausdorff's formula). All of these cases have been implemented too.

In summary, in the latest update of Physics the combination and expansion of powers and exponentials using combine and expand now takes into account the noncommutative character of the exponents and the value of their commutator, and there is the option of having this combination happening automatically, for both noncommutative and commutative algebraic objects in general.

Other relevant changes more related to Physics are described in the PhysicsUpdates.mw distributed inside the zip that contains the updated Physics.mla linked in the "Maple Physics: Research & Development" webpage.

 

Hi, 
A new Physics:-Library:-SortProducts command got added to the Library, addressing the need for reordering operands in noncommutative products (Physics:-`*` and Physics:-`.`) in different ways (optional arguments of SortProducts). Note: SortProducts returns an expression mathematically...

(Presentation in Spain a month ago focusing on educational and research use)

ODEs and PDEs

 

"Computer algebra systems have evolved into powerful environments for studying and solving differential equations."

 

Some polemical questions:

 

Can a Computer Algebra system compute numerical ODE solutions as fast as for instance C or FORTRAN code ?

   

Can a computer really be more useful than a good book for finding exact ODE and PDE solutions ?

   

Aren't these computer algebra environments more like a black-box approach to the problem ?

   

Can we really study  the "differential equations" behind a problem using Computer Algebra as we would do by hand?

   

Is there something fundamentally relevant regarding ODEs and PDEs that we can only do with a computer?

   

___________________________________________________________________________

 

Special Functions

 

"Special functions, their inter-relation and representations become alive within a computer"

Conversions between mathematical functions

   

The FunctionAdvisor project

   

Differential Polynomial Form for non-polynomial expressions

   

___________________________________________________________________________

Conclusion

 

"Research and education are two things highly inter-related"

 

  

-  Constructive learning processes are mostly based on the building of logic structures by testing conjectures and analyzing the results. The proportion between success (the conjecture solves the problem) and frustration plays an important role as an emotional (+/-) accelerating factor for the whole "learning & discovery" process.

-  The simultaneous analysis of a greater number of results turns apparent the underlying logic structures more rapidly, and can strengthen the intuition unexpectedly.

  

- Genuine learning processes only happen when the individual who is learning participates actively.

  

- Inspiration is a function of intuition, excitement and fun, transformed into results through heavy exploration.

Symbolic computation can be used with these purposes, perhaps as the most important educational and research tool available at present.

___________________________________________________________________________

 

 

Santander_talk.pdf   Download Santander_talk.mw

 

Edgardo S. Cheb-Terrab
Physics, Maplesoft

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