How can I order the factors when using the sym and latex functions?

Hi,

is it possible to control the order of the factors when using the sym and latex-functions?

E.g.

str = (5/8)*x;

out = latex(sym(str));

% produces out='\frac{5\, x}{8}'

% corresponding to (5*x)/8 and not (5/8)*x (='\frac{5}{8}x') as desired

I know these are mathematically identical, but I use the output for educating students and for them the second expression is easier to understand. I have thousands of expressions so need to find a way to do this automatically.

Thank you in advance, Morten

Answer 1

[Walter Roberson]

No, the Symbolic Toolbox does not offer an way of giving preferences on how the terms are to be formatted or ordered.

In this particular case the work-around would be

out = [latex(coeffs(str,x)),latex(x)]

coeffs() with two outputs is generally useful for formatting terms of a polynomial. For non-polynomial expressions, you might need to start using children() .

Unfortunately, in order to find out the basic operation that you are getting the children of, you need to pop into the symbolic engine:

feval(symengine, 'op', str, 0)

which in this case would get you sym('_mult'); you might also see _power or _plus or _not or _less or _leequal or _SYM_equal or _or

[MortenJ]

Thanks, nice and versatile solution.

Answer 2

[Ankitha Kollegal Arjun]

Morten,

You could try the following:

1. Factorize the required symbolic expression using factor(). (result will be a symbolic vector)

2. Use the latex() function on each element of the above symbolic vector and concatenate the results to obtain the desired latex format.

>> syms x
>> str = (5/8)*x;
>> temp = factor(str);
>> out = [latex(temp(1)) latex(temp(2))]

out =

\frac{5}{8}x

[MortenJ]

Works great, thanks. I realized I also had to deal with a lot of other equation-formats, so picked the suggestion by Walter below, which was able to deal with those as well, but thanks for helping out.