Hi All
In Mathcad, I usually type a variable with subscript by using dot(.)
For example A.x then it will show A with a subscript x.
Is that possible in SMath? or similar?

I know in SMath there is a function index by pressing [
but this is different with .

Thanks for any information

Regards
Waluyo

Hello,

I was playing a bit with variable names.


It seems that it is advisable not to use these character in the variable names. Interesting to note that this variable could be also defined:
diff(abc)←98
By typing "diff(" which will produce placeholder with prime
diff(#)
In this placeholder we can put a variable name.
I do not know if all of this could cause some problems or not.

On the other hand, there is no problem of using characters in variable names from different languages. Mathcad could not do this for a long, long time (actually I do not know if this could do even now in the recent version).

Regards,
Radovan

EDIT: Actually my first intention for this post was to mention that literal subscript (.) and index ([) are mentioned here few times from Mathcad users. From my experience as a Professor, I found it very confusing sometimes and hard for explaining to my students. Maybe the solution is (as Andrey suggested) to have only one - and not both.

Edited by user 17 November 2009 23:06:13(UTC)  | Reason: Not specified

Glad to hear you are planning to implement variable subscripts. This would be an opportunity to one-up MathCAD; I have long wished to have the bar or dot above variable names to indicate average or time derivatives. My worksheets often have cumbersome variable names like Q.dot etc.

I just discovered this program today but I am very excited to use it and watch it develop. Great work to the devs!

Hello,

(SMath Studio version 0.88 is current as I write this.)

About Andrey's statement:


It might be worthwhile to keep these separate. What the computer does with A.x (at least in Mathcad) is different than with A[x

That is, A[x uses x as an index to select one element from A, but A.x names a variable which has nothing to do with the variable (matrix) A.
* The (.) is just part of the variable name, so that there is hardly any difference between A.x and Abx. There can be a worksheet that refers just to A.x, without variables A or x existing at all.
* On the other hand, ([) can be thought of as a function with arguments A and x that "does something" with A and x to get or set a value. Arguments A and x are required to exist as separate variables in order for A[x to be valid.

The previous paragraph might help with Radovan's concern about explaining the difference between ([) and (.) to students / new users.

Furthermore, maybe future versions of SMath Studio could have the following 2 formatting features:

1. ([) could be formatted with parentheses and an arguments separator, similar to the following (depending on localization):



(.) would be formatted as ([) (with one argument) is today, that is, without the parentheses ().

2. The "(" character could be disallowed in variable names (if it is not already).

As a result, someone looking at an SMath Studio worksheet could tell at a glance whether each subscript was a ([) or a (.) That is, ([) would have parentheses and (.) would not.

I think that combining the 2 kinds of subscripts into one could cause problems. For example, suppose the user has a matrix called A but also wants to define a scalar called A.x:


If (.) were separate from ([), then (.) could be used in this example, and there would be no error.

---

It seems to me that an expression like the following (using the formatting features suggested above) could still be evaluated (differentiated) just fine if (.) were added to SMath Studio:



According to the formatting features suggested above, the subscripts in that expression would be ([)

I assume that Andrey mentioned this expression just to point out that SMath Studio has the potential to be more versatile than Mathcad when it comes to subscripts.

If I am misunderstanding, maybe someone can clarify for me.