index notation symbolic toolbox

example: fi = sym('fi',[1 2]) fi =

[ fi1, fi2]

I want this to be: fi =

[ fi(1), fi(2)]

This in order to use outcome of symbolic manipulation directly in my matlab code.

[Dinant]

Nobody?

[Dinant]

Really? Somebody of the Mathworks?

[Sean de Wolski]

Dinant, I answered your question and provided you with code that does exactly what you asked for. If it's not, please clarify in your comments what you actually want.

[Dinant Kistemaker]

Thanks for the help, but you did not. I have reinitiated my post in hope I can get a workaround for this...

Answer 1

[Sean de Wolski]

>> fi = sym([1,2])

?

Answer 2

[Dinant]

hmmm, what do you mean with the question mark?

[Sean de Wolski]

Is this what you're looking for?

[Dinant]

that gives: fi =

[ 1, 2]

so no.

[Sean de Wolski]

Which can then be indexed like this:

fi(1)
fi(2)

Which is what you asked for.

[Dinant]

No it is not. your suggestion simply outputs 1 if i type fi(1). I know I can index it, but, as mentioned in the original posting, I want the output indexed.

if I type fi, I want the answer to be: fi = [ fi(1), fi(2)], or if I type sin(fi(1) I want the output to be sin(fi(1)) and not sin(fi1).

[Sean de Wolski]

Dinant, this is what my code does:

clear fi;
fi = sym([1 2]);
sin(fi(1))

It will not return two separate outputs because this is not how MATLAB works. Consider the same question for doubles:

[D(1) D(2)] = [1 2]; %error!

You would need to do this on two lines:

D(1) = 1;
D(2) = 2;

Knowing [1 2] upfront you would want

D = [1 2]

Then

D(1)

[Dinant]

I appreciate your help.

My question relates to the fact that directly want to use the output of symbolic manipulations in my matlab code that is vectorized. Symbolic output is not. It makes from fi(1) fi1. I do not want that. I want the output to be in terms of fi(1), fi(2), etc.

[Sean de Wolski]

What release are you using? Because on mine(R2013b) it creates a 1x2 sym

Code:

fi = sym([1 2])
size(fi)
sin(fi(1))

Printed:

fi =
[ 1, 2]

ans =
   1     2

   ans =
           sin(1)

Answer 3

[Walter Roberson]

syms fi

then fi(1) will be fi(1)

[Dinant]

nope...

>> syms fi >> fi(1) ans = fi

Answer 4

[Dinant Kistemaker]

I am still very much looking forward to an answer to my question. It is really annyoing that the printed format is not in vector notation. I want to use the output for some symbolic manipulations in my code and I want to use vector notation.

if I type:

fi = sym ('fi',[1 3]);

x=cos(fi)

>>x =

[ cos(fi1), cos(fi2), cos(fi3)]

I would very much want to have the answer in vector notation like:

x =

[ cos(fi(1)), cos(fi(2)), cos(fi(3))]

Answer 5

[Dinant Kistemaker]

Nobody???

Answer 6

[Dinant Kistemaker]

I am so looking forward to an answer to my problem...

Somebody from the Mathworks?

[Steven Lord]

If you want an official MathWorks answer please contact Technical Support directly using the telephone icon in the upper-right corner of this page.

I suspect you will not be able to do what you want with sym or syms. Depending on what "use outcome of symbolic manipulation directly in my matlab[sic] code" means the matlabFunction function may be of use.