Evaluate expression for a variable(s) set to a number

#1 Publicado: 10/4/2014 16:26:17

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Hi All,

So I am using Smath Studio for personal projects (I am converting from Mathematica that I no longer have access to).

Here is a very simple task i need to do and yet after 30 minutes of search I still do not know how to achieve it:

Say I have g=h+j-k+100

How do I evaluate g for h = 1, j=2, k=3?

I have found that if g=j+2, setting g(j)=g will do the trick for one variable only: g(1)=3, while g=j+2.

In mathematica it would be as simple as g/.{h->1,j->2,k->3}

This would come in very useful if you would want to evaluate function that has more than one variable.

Many thanks!

#2 Publicado: 10/4/2014 17:46:56

Alexander O. Melnik

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Thank you ioan92! That is really what I needed.

Also what would be the best tutorial you can recommend on SMATH? Either English or Russian.

Thanks!

#3 Publicado: 10/4/2014 17:49:40

Martin Kraska

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The FunctionsExtensions plugin provides the at() substitution function with special operator formatting. This exploits the symbolic storage of the expression in the variable g.

Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9

#4 Publicado: 10/4/2014 17:54:11

Alexander O. Melnik

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That looks very interesting as well, will experiment. Thanks!

#5 Publicado: 17/4/2014 10:36:20

Alexander O. Melnik

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Hi everyone!,

Not sure if this would be a bug but at() function does not seem to work while evaluating fuctions that include Min() or Max().

See workbook and photo attached.

Thanks!

A 2 usuarios les gustó este mensaje

Martin Kraska 17/4/2014 18:08:00, Davide Carpi 19/4/2014 3:42:00

#6 Publicado: 17/4/2014 11:10:56

Martin Kraska

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Confirmed. This is bug of Min() and Max(). Apparently they always try to return a numeric result, regardles of what the optimization setting is. If they would return themselves with evaluated/preprocessed arguments, at() would work, as the example with max() shows.