Variables evaluation

Variables evaluation - Symbolic to numerical substitution and evaluation - Messaggi

#1 Pubblicato: 12/04/2022 16:14:10
Mario Acevedo

Mario Acevedo

0 apprezzamenti in 11 post.

Gruppo: User

Dear all:

I am new to Smath Studio, great software!

Even I am new to its usage, I am trying quite complicated calculations I guess.

I am putting the following lines:

substitution.png

As you can see, I am using Maxima plugin and the Maxima function ev() to substitute values in the symbolic variable. I have some specific questions:
1.) Is there an alternative way to do this kind of calculations without using the Maxima plugin?
2.) v is a system of values, each value is an equality, is there an automatic way to generate a system of values?

Thank to all the people that could help.
#2 Pubblicato: 12/04/2022 17:04:06
Martin Kraska

Martin Kraska

1.361 apprezzamenti in 2.275 post.

Gruppo: Moderator

I can't open your image. From what you describe, you might want to use the substitution function at() from Custom Functions plugin.

at.sm (22,23 KiB) scaricato 1288 volta(e).
Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9
#3 Pubblicato: 12/04/2022 18:16:56
Jean Giraud

Jean Giraud

983 apprezzamenti in 6.866 post.

Gruppo: User

Attach your Smath document.
#4 Pubblicato: 12/04/2022 18:51:35
Jean Giraud

Jean Giraud

983 apprezzamenti in 6.866 post.

Gruppo: User

at(3) Demo.PNG
#5 Pubblicato: 12/04/2022 19:41:47
Mario Acevedo

Mario Acevedo

0 apprezzamenti in 11 post.

Gruppo: User

Sorry about the image, now the image is visible.

What I want is to iterate over a set o values to substitute in a variable a store the results in a variable, something like this:

substitution.png

Is there a way to do this substitutions in an iterative way?.
I mean: using a set of programming lines?

In this worksheet I copied and pasted the lines to perform the iterations, but in a general problem solving it is desirable to iterate automatically.
#6 Pubblicato: 12/04/2022 20:20:21
Mario Acevedo

Mario Acevedo

0 apprezzamenti in 11 post.

Gruppo: User

Here is the Worksheet:

Worksheet1.sm (10,95 KiB) scaricato 1253 volta(e).
#7 Pubblicato: 12/04/2022 20:45:20
Mario Acevedo

Mario Acevedo

0 apprezzamenti in 11 post.

Gruppo: User

Thank you Martin Kraska, at works fine and is what I needed.

It seems that to iterate I have to declare the sys vector by myself, isn't it?

Thanks a lot!
#8 Pubblicato: 12/04/2022 21:29:50
Jean Giraud

Jean Giraud

983 apprezzamenti in 6.866 post.

Gruppo: User

Wrote

What I want is to iterate over a set o values to substitute in a variable a store the results in a variable, something like this:


An iterative process is a solving process.
As you say, you just want to plug something from command line.

Command Line UNK.PNG
#9 Pubblicato: 12/04/2022 23:45:16
Mario Acevedo

Mario Acevedo

0 apprezzamenti in 11 post.

Gruppo: User

wow!, this is what I was looking for!!!, THANK YOU very much Jean Giraud!

#10 Pubblicato: 13/04/2022 07:41:58
sergio

sergio

127 apprezzamenti in 342 post.

Gruppo: User

I take inspiration from Jean, but I use the Vectorize function and I forget the size of U

Mostra spoiler


FunzioniVettori.sm (6,37 KiB) scaricato 1242 volta(e).
sergio
#11 Pubblicato: 13/04/2022 08:21:09
Martin_B

Martin_B

22 apprezzamenti in 84 post.

Gruppo: User

Pay attention! The definition of M(r) doesn't make much sense.

Screenshot 2022-04-13 131758.png
#12 Pubblicato: 13/04/2022 08:41:51
Jean Giraud

Jean Giraud

983 apprezzamenti in 6.866 post.

Gruppo: User

Wrote

I take inspiration from Jean, but I use the Vectorize function and I forget the size of U


Superb Sergio ... added in the main document.
#13 Pubblicato: 13/04/2022 09:48:44
overlord

overlord

600 apprezzamenti in 1.381 post.

Gruppo: Moderator

An algorithm can also be used.
It may be simpler by this way.

Regards

Worksheet1_algorithm.sm (4,69 KiB) scaricato 1283 volta(e).

2022-04-13_15-46.png
#14 Pubblicato: 13/04/2022 14:10:35
Mario Acevedo

Mario Acevedo

0 apprezzamenti in 11 post.

Gruppo: User

Nice implementation!!

Just a question, does the S variable had to be declared and dimensioned previous to its use?

I will try the code asap!

Thank you !
#15 Pubblicato: 13/04/2022 14:48:08
Martin_B

Martin_B

22 apprezzamenti in 84 post.

Gruppo: User

You should always define variables used as arrays in function before assigning elements.

Worksheet1_algorithm.sm (8,04 KiB) scaricato 1270 volta(e).

Screenshot 2022-04-13 194527.png
1 utenti hanno apprezzato questo post
sergio 13/04/2022 16:00:00
#16 Pubblicato: 13/04/2022 16:04:10
Jean Giraud

Jean Giraud

983 apprezzamenti in 6.866 post.

Gruppo: User

Wrote

Just a question, does the S variable had to be declared and dimensioned previous to its use ?


No, it sets by itself within the for loop.
Wise to clear within the algo ... U:=0
That will avoid interaction with else U above document.
Algo style is an immense companion in Smath.
Personally, I use it as much as possible,
it enables the local command line.
Cheers ... Jean.

Maths algo style MATRIX in_extenso.sm (5,88 KiB) scaricato 1294 volta(e).


#17 Pubblicato: 13/04/2022 16:47:50
overlord

overlord

600 apprezzamenti in 1.381 post.

Gruppo: Moderator

Wrote

You should always define variables used as arrays in function before assigning elements.


MarB is dead right.
Array variables should be considered carefully if they will be redefined multiple times.
Or they can be undefined and named uniquely. I tend to name variables in functions this way.
You can find below how I would name your functions variables.
Pretends mess of misusage.

Regards

worksheet1.png
#18 Pubblicato: 13/04/2022 17:55:24
Davide Carpi

Davide Carpi

1.443 apprezzamenti in 2.936 post.

Gruppo: Moderator

Wrote

Just a question, does the S variable had to be declared and dimensioned previous to its use?



It isn't required but it is good practice. If the variable name already exists you might fall in some unexpected cases when the dimensions are different. In addition to the above suggestions, you can use also a Clear(S) as initializer.
If you like my plugins please consider to support the program buying a license; for personal contributions to me: paypal.me/dcprojects
  • Nuovi post
  • Nessun nuovo post