What does \\\r\n mean ?

Using symbolic variables in matrix-multiplication with elements consisting of trig-functions I came across a symbol that I have not seen before. It shows up in two elements in the result:

 38769523591\\\r\n65965*Dq3*sin(2*q2 + q3)

and

-\\\r\n 1578177954729427/1073741824

What is this mysterious operator ? I tried using vpa(), but still the operator got promped. However, using

vpa(ans,2)

the operator disappeared. I guess it has something to do with numerical accuracy in the symbolic math engine...

[KSSV]

Copy the full code.

[Stephen23]

Have a look at the "Special Characters" listed here:

https://www.mathworks.com/help/matlab/ref/fprintf.html#inputarg_formatSpec

[Steven Lord]

I agree with KSSV. Please post a small sample of code with which you can reproduce this behavior so that we can try to reproduce the behavior as well.

[Ronny Landsverk]

I have no problem with posting code, but in this case there are many calculations performed prior to this behaviour... Hence, the symbolic expressions are quite long! I can attach the functions used in the calculations and show how to re-create the behaviour.

 q = sym('q',[3,1]);
 Dq = sym('Dq',[3,1]);
 DDq = sym('DDq',[3,1]);
 M = inertiaMatrix(q);
 C = corCenMatrix(q,Dq);
 G = springMatrix(q);
 T = M*DDq + C*Dq + G

[Jan]

Does it shed any light to your problem that \r\n is the standard DOS line break?

[Ronny Landsverk]

Hi Jan Simon. Yes it does. However, I think this is a bug since these show up as part of an answer prompted by MATLAB... Do you have a comment ?

Answer 1

[Jan]

In format specificators e.g. in sprintf the backslash is used as escape character: the following character get a special meaning: \r is a "carriage return" and \n a "new line". Both together are used by DOS applications as line break. To get a backslash charater, \\ is used.

Remark: You can ask an internet search engine for "\r \n" also. I like this forum very much, but e.g. Google finds an answer in less than a second.

[Ronny Landsverk]

Hi Jan Simon... new line - got it. However, I think this is a bug since these show up as part of an answer prompted by MATLAB... Do you have a comment ?

[ali]

I have a same problem, how to use new line???

[Walter Roberson]

strrep(TheOutput, '\\\r\n', '')

Note that in cases where you get these characters, it would not be uncommon to see a message about truncated output. To view the whole output, see the work-around I gave in the link in my answer.

Answer 2

[Walter Roberson]

It is a bug in the output of long symbolic expressions. I submitted a report about it a few months ago. It would not hurt to submit a report yourself, so that they know I am not the only person affected.

[Walter Roberson]

See my more detailed explanation at https://www.mathworks.com/matlabcentral/answers/337896-odd-r-n-output-from-symbolic-multiplication#answer_265002

Answer 3

[Mohamed Abdelhamid]

I did encounter that "\\\r\n" in some really long symbolic expressions. All I did was use find/replace to replace it with nothing. It did work pretty nice after that and the calculations were indeed correct.

[Walter Roberson]

That will not generally work; see https://www.mathworks.com/matlabcentral/answers/337896-odd-r-n-output-from-symbolic-multiplication#answer_265002