Re: Digital Twin applied to Software

This is my experience that gave rise to Digital Twin idea.
The program is commercially very successful but is humongous.
It has a command called Update. One of the tasks was Propagation which 
is 30 years old C code embedded in C++.
Many individual functions are hundreds up to a few thousand lines long.
Everyone admits no one understands the code well yet it constantly needs 
tweaking. The fear is palpable.
Wouldn't a rewrite of just Propagation in Smalltalk be a quick way to 
understanding Propagation better?

Aik-Siong

Cesar Rabak wrote:
> This
>
>     ... only requirement is that the same inputs give the same desired
>     outputs.
>
>
> is  a typical consequence of both (and it can be extended to a large 
> number of languages/technologies) be Turing Complete.
>
> In other realms, like Function Point Analysis, this is the paradigm: 
> if two systems are equivalent (using the definition above) then the 
> advantages of the approach, including cost, time to deliver, etc. can 
> be analysed.
>
> Your suggestion of the use of two paradigmatically different 
> programming languages to "discover" in one and implement in other 
> "fast" is not amenable to real systems, only to toy programs where the 
> problem is chosen carefully beforehand to "fit" both languages.
>
> Programming shops already strive to have the right balance of 
> technologies in order to have "the best of the 'n' worlds".
>
> When in one language (C++) the decision is a command, while in 
> Smalltalk the Boolean is an object the impedance mismatch in 
> attempting any reasonable problem which has conditions, loops, etc. 
> will show that the prototype in Smalltalk could not be used to "port" 
> the algorithm as the details that effectively make the program work in 
> one language would be far away in the other.
>
> Besides, most of the present problems in development are less about 
> algorithms and more about integrate large bunches of functionality 
> written in several languages, different eras to solve a business problem.
>
>
>
> On Tue, Nov 8, 2022 at 3:02 PM Aik-Siong Koh <[email protected] 
> <mailto:[email protected]>> wrote:
>
>     Digital Twins do not need any mapping within their boxes. The only
>     requirement is that the same inputs give the same desired outputs.
>     Total
>     independence would enhance software quality to the max.
>
>     Now, I am proposing that one twin is used for discovery of algorithms
>     while the other implements the desired algorithm fast. We are porting
>     algorithm not porting Smalltalk code necessarily.
>     We truly want and can have the best of both worlds.
>
>     Thanks,
>     Aik-Siong
>
>     andre wrote:
>     > As said, there is no formal mapping.
>     >
>     > One could enforce a common denominator (design patterns) at both
>     ends, like shared pointers for all objects, only virtual methods
>     at the C++ end and strong typing at the Smalltalk end. In reality
>     it get's a lot more complex than that (need for class-side virtual
>     methods, reflection).
>     >
>     > That would rob each side of its unique advantages. You would get
>     something a C++ compiler can compile, but not C++. Not much would
>     be left of the performance gain.
>     >
>     > The new Smalltalk compiler would have to deal with strong typing
>     and the exceptions and dependency management it implies. It'd be a
>     new language.
>     >
>     > Porting Smalltalk to C++ involves a lot of deep thought and
>     manual work that can be assisted by tools only to some extent.
>     Porting C++ to Smalltalk is even more daunting (almost impossible,
>     I would say) except for simple classes and domains.
>     >
>     > Another approach is to embedd a Smalltalk interpreter or VM into
>     a C++ application. That way you get a solid foundation with
>     dynamic extensibility. Should work fine for CAD.
>     >
>     > Andre
>     >
>     > --
>     >
>     >> On 7. Nov 2022, at 03:57, Aik-Siong Koh <[email protected]
>     <mailto:[email protected]>> wrote:
>     >>
>     >> Andre:
>     >>
>     >> You understand my Digital Twin idea perfectly. Your statement
>     sums it all:
>     >> "The ideal case for using both languages together might be to
>     explore uncharted terrain with Smalltalk and port to C++ after a
>     sound architecture has settled."
>     >>
>     >> Anyone doing this systematically? How to promote Digital Twin?
>     How to turn this Smalltalk advantage into a business?
>     >>
>     >> I am applying idea to Pharo and OpenCascade to create Digital
>     Twins of CAD software. Any feedback or interest would be greatly
>     appreciated.
>     >>
>     >> All the best,
>     >> Aik-Siong
>     >>
>     >
>