Why does the vectorize operation fail while it seems to be safe to use an explicit loop?

6-2-Bug.sm (27 KiB) downloaded 66 time(s).

Wrote

Why does the vectorize operation fail while it seems to be safe to use an explicit loop?

Hi Martin. Because you have just only one function which can't be vectorized: the norme or dot product of vectors.



Best regards.
Alvaro

Is that just by observation or is there a fundamental obstacle?

Wrote

Is that just by observation or is there a fundamental obstacle?

Hi. I guess that it is fundamental.

Some notes about how other CAS handle this issue.

Pretty old matlab version, from its symbolic toolbox



The help page from the newest version



So, it looks like they have some issues with automatic vectorization.

With maple it is very uncomfortable, you need to use map even for simple cases



Wolfram's solution is very practical: Function with attribute 'Listable' expands over lists



But for make a table you actually need a loop or the Mathematica's Map function.

Best regards.
Alvaro.

Wrote

Why does the vectorize operation fail while it seems to be safe to use an explicit loop ?

Set the demand in local definition mode ...
new(t):=|a(t)
vectorize and equate


6-2-Bug Doctored.sm (29 KiB) downloaded 51 time(s).

Thanks Alvaro and Jean. Here is a reduced working example.

When a scalar function involves scalar products then it must be defined in a line()-block in order to be vectorize()able.


Worksheet13.sm (5 KiB) downloaded 48 time(s).