Wrote

Hello Uni,

The plugin is broken again since Smath v.6962 (I'm sure only with ..62 at the end).
I've spent half of an hour and located the issue.
It is a tiny piece of a big worksheet.

Best regards

mapledoesntworksince6962.sm (21 KiB) downloaded 90 time(s).

There aren't maple() funtions involved here, therefore can't be a maple tools issue.

You can fix it in this way:

Thanks Davide,
But I wrote the f_poly(v) few years ago and there were no troubles till 6965b.
It's strange that even minor update requires to review very old (considered reliable) worksheets.
f_poly() is pure numerical function and contains tons of evals .
How is it possible to corrupt posterior symbolic calculations?

Wrote

But I wrote the f_poly(v) few years ago and there were no troubles till 6965b.
It's strange that even minor update requires to review very old (considered reliable) worksheets.
f_poly() is pure numerical function and contains tons of evals .
How is it possible to corrupt posterior symbolic calculations?

I haven't checked if there are differenes in p content between the versions but I see that in the problem is involved cases(...); if you move the eval fomr the p definition to the "if" condition of cases you have the script working again...

Wrote

Support for evaluation plug-ins improved.

I can't check it right now but this is probably the change that makes the difference (SS 0.99.6970).

Hi. Just a very small issue with subscripts:



Best regards.
Alvaro.

Wrote

Hi. Just a very small issue with subscripts:

Yellow is OK, a one element vector.

Hello Uni,
Recently I found another problem in symbolic calculations that probably related to maple plugin.
Let see the example in attachment.
This is simple example of constructing of system of equations for circuit of 3-rd order.
I need 2*3+2 equations some of them define frequency response, some define of the position of minimums/maximums or the transfer function.
The problem happens with taking derivatives. Smath can't calculate them without involving maple plugin. Try disabled equation for H1(n,k,b,w).
But using maple(simplify()) it does it right. After this step H1(n,k,b,w) became useless. Any symbolic expression that uses it returns "empty".
But if I use copy-pasted output of the H1(n,k,b,w), everything works fine. It looks like I need to force the symbolic result to be evaluated at some point,
similar to eval() for numeric calculations, but I don't understand how to do that.

equ3.sm (33 KiB) downloaded 85 time(s).

Hi. Try this.

equ3.sm (32 KiB) downloaded 88 time(s).

Best regards.
Alvaro.

Alvaro,
Your version works. Do you have an idea how to generate sub-indexes from Range ? I need to generalize it for different n.
Best regards,
Igor

Wrote

The problem happens with taking derivatives.
Smath can't calculate them without involving maple plugin.

maple not needed to take derivative, directly from Smath native.



TOM.sm (17 KiB) downloaded 70 time(s).

Wrote

Do you have an idea how to generate sub-indexes from Range ? I need to generalize it for different n.

Hi Igor. Use this



equ3.sm (32 KiB) downloaded 84 time(s).

Best regards.
Alvaro

I think that here is the same problem that I mentioned earlier. maple() function doesn't know how to work with external definitions. Arguments must be explicitly defined. This limits the possibilities for its use. This is due to uncertainty - it is not clear what function is implied in the expression: maple diff() or smath diff(). Same for int() and others. I don't know how to solve this.

Wrote

I think that here is the same problem that I mentioned earlier. maple() function doesn't know how to work with external definitions. Arguments must be explicitly defined. This limits the possibilities for its use. This is due to uncertainty - it is not clear what function is implied in the expression: maple diff() or smath diff(). Same for int() and others. I don't know how to solve this.

Hi. This is a workaround: use maple's 'value' function, which convert inert versions of some procedures to the actual procedures for evaluation. Usually, inert version have the same name, but with the first letter in uppercase.

Notice that for Diff you must to disable Maxima plugin.



Best regards.
Alvaro.

... ? any suite/comment

I'd like to clarify the problem. There were two issues in my worksheet.

1. Symbolic differentiation works strange: if you evaluate dA/dx symbolically and A is not a function of x it returns 0. That is correct.
But if A is an indexed variable it returns dA[k]/dX = dA[k]/dx, that's wrong, A[k] is not a function of x. That was the reason to change indexes to subscripts.

2. I found workaround using maple(simplify(dA[k]/dx))=0. I can get right result in this case, but I can't use it in futher calculations. This is the main issue.
If I'd be able to use the symbolic result as it was generated by maple plugin everything would be fine. Instead, Smath postpones symbolic evaluation and eventually
reports "empty" or something like that when the expression gets too complicated.

Wrote

I'd like to clarify the problem. There were two issues in my worksheet.

The first issue is the undefined upper limit in the summation.
I made it Floor [in conformity to Mathcad]
The 2nd issue is that maple has nothing to do in there.
Native Smath expands symbolic, that you just assign.
Once in there, you have two options:
1. Infinitesimal derivative
2. d/dx Smath operator fully compatible with expand(μ,b,ω)
What is the problem ?
Naturally, the vector of 'b' does not come from the sky
You must create from source, or otherwise create from
some kind of creator. I just put anything for demo
but it can be anything else as well for you to try.

Interesting brain storm ... Jean

0Appendix [BirdNest].sm (16 KiB) downloaded 68 time(s).

Jean,
Regarding issue #1 I attached sym_diff_issue.sm (3 KiB) downloaded 68 time(s)..
Where do you see "undefined upper limit" ?
For issue #2 I attached equ3+remarks.sm (33 KiB) downloaded 70 time(s). with remarks.
Regards,
Igor

Wrote

Where do you see "undefined upper limit" ?

From some expansion of your original with odd 'n' [n=3]
Smath reported the error
just to confirm wrt Mathcad that 'Floor' by default
Will check the other issue tonight.
Jean

Wrote

Where do you see "undefined upper limit" ?

For the other issues equ3_remarks, your programs are incorrect.
Set n=3 to see something

equ3_remarks.sm (66 KiB) downloaded 65 time(s).

Igor,
Your working algorithm is exemplified part 2 of the attached.
Try it starting n>= 3.
From there, past the derivative, what else should it be doing ?

Cheers ... Jean

0Appendix [BidirectionalPulse].sm (22 KiB) downloaded 58 time(s).

Thanks Jean,
Don't waste your time, I already have solved the problem.
The n supposed to be odd number in the range 3,5,7,9,11. The practical case was 9.
The goal was to derive system of 22 equations. They looked too complicated for doing it manually.
I posted simplest case n=3 just to illustrate the issues I've encountered.
Sorry, I can't go into details, that is a kinda commercial project .