Sym

Hi,

how can I change format of sym number? For example:

a=sym(2.34353453465464);
b=sym(4.6546455789879324352);

format short
c=a*b

Format short doesn't work.

Thanks

[Sean de Wolski]

also note, b is converted to double before sym and some precision is lost

Answer 1

[Andrew Newell]

Use vpa, e.g.,

c = vpa(a*b,4)

[john]

big thanks

[john]

Hi, I have problem with my code: vpa works for "result", but I need show result in the uitable1, but for "res" command vpa doesn't work.

matrix=[A B;C D]

a=simple(matrix\X);

b=sym(a)

result=vpa(b,4)

f=size(result);

for i=1:f(1);

for j=1:f(2);

res(i,j)=cellstr(char(result(i,j)));

end

end

set(handles.uitable1,'Data',res);

[Andrew Newell]

I suggest you make a new question of this.

[john]

Hi,

if a=vpa(sym('ddddddd'),3), result is ddddddd

if a=vpa(sym('-ddddddd'),3) result is -1.0*ddddddd, but I don't like it, I would like have -ddddddd..

it is possible?

[Andrew Newell]

I can't reproduce your result. If I type

vpa('1.234567',3)

vpa('-1.234567',3)

I get 1.23 and -1.23.

[john]

You result is OK, but try it for symbolic objects for example vpa(sym('ddddddd'),3)......result is -1.0*ddddddd,,,,,or you have different result?

[Andrew Newell]

I added sym() and the result was the same. What version of MATLAB are you using?

[john]

7.12.0.635 (R2011a), and you?

Did you try with vpa(sym('-ddddddd'),3) also?

[Walter Roberson]

MuPAD's unary minus gets converted automatically to -1 times the value, and there is no way to stop that conversion.

Overriding MuPAD's pretty-printer formatting for an expression is not much fun.

[john]

ok,

thank you again

[Andrew Newell]

I was using the Maple Toolbox.