Please see attached example.
sym_diff_issue.sm (3 KiB) downloaded 96 time(s).

Wrote

Please see attached example.

What about completing the code to make it profitable ?
Not new the derivative of a constant is 0.

Hi Tom. maple() knows how to eval diff because, as plugin, Viacheslav (uni, plugin author) know how to handle the function el(A,k). But notice what happen with an unknoun function, like El(A,k). So, problem here is what to do with the SMath el(A,k) with the operator diff.



Best regards.
Alvaro.

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Wrote

Hi Tom. maple() knows how to eval diff because, as plugin, Viacheslav (uni, plugin author) know how to handle the function el(A,k). But notice what happen with an unknoun function, like El(A,k). So, problem here is what to do with the SMath el(A,k) with the operator diff.

As you mentioned Ei(x), like many special functions,
you may have to rescue from infinitesimal analysis,
the ancestor of CAS.

sym_diff_issue (more).sm (12 KiB) downloaded 64 time(s).

I think this is a bug.
If there is no evidence that variable A[k] depends on x, dA[k]/dx should be immediately set to 0.
This is the way how symbolic engine of Wolfram Mathematica works.
Probably, I made a mistake mentioning "indexed functions", the right subject name should be "indexed symbolic variables" instead.
In real case A[k] were indexed unknowns in the system of equations.
I intentionally made this example as simple as possible to make it evident.

Wrote

In real case A[k] were indexed unknowns in the system of equations.
I intentionally made this example as simple as possible to make it evident.

You can do lot more from lot less for real project:
1. get your function from index
2. get the partial derivatives wrt parameters in function.

sym_diff_issue (more).sm (23 KiB) downloaded 93 time(s).