[Scilab-users] Regarding simple numerical operations result display.

[Stefan Du Rietz]

On 2013-03-20 14:38, Serge Steer wrote:
--------------------
> Le 19/03/2013 13:32, Stefan Du Rietz a écrit :
>> On 2013-03-19 11:43, Serge Steer wrote:
>> --------------------
>>> Le 19/03/2013 11:26, Dang, Christophe a écrit :
>>>> De la part de Stefan Du Rietz
>>>> Envoyé : mardi 19 mars 2013 11:10
>>>>
>>>>> But gsort is a built-in function (and very efficient):
>>>> I just wonder if it can be as efficient if you write your own
>>>> function
>>>> and then compile it with comp().
>>> Note that comp is now made automatically when you define a Scilab
>>> function, but comp only generate a pre-interpreted code not a
>>> processor binary code so gsort which is a built-in (processor binary
>>> code) will be in any case much more efficient.
>>>
>> Serge, can you please also tell us what "pre-interpreted" implies
>> regarding loops?
> Nothing special is done for loops. The pre-interpretation  just parses
> the original code, checks its syntactical correctness and transforms
> it into a reverse polish notation more appropriate for stack automaton.
>
> Most of the time spent in execution of Scilab code is used for
> handling type and dimension checking and the decision tree relative to
> the types and dimensions with select the final piece of code that will
> realise the computation.
>
> Example: imagine the A+B Scilab instruction,  it implies the following
> set of tests and routing:
>
> Get location of A in the memory
> Get location of B in the memory
> What is the type of A  (1, 2, ...) -->assume 1
> What is the type of B  (1, 2, ...) -->assume 1
> What is the dimension of A (empty, scalar, array) -->assume array
> What is the dimension of B (empty, scalar, array) -->assume scalar
> Is A real or complex --> assume real
> Is B real or complex --> assume real
> Is there enough memory to store the result  -->assume yes
> Finally call the code that adds a double scalar to each entries of an
> array ou doubles
>
> So at least 10 operations to select the proper leaf of the tree. It is
> neglectible if A is a big array, but significative if A is just a 1 by
> 2 array
>
>
> Serge
>
Very good! I have not found this information elsewhere.

Thank you very much!

>> Best regards
>> Stefan
>>
>>
>>
>>
>
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