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What does \\\r\n mean ?

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Ronny Landsverk
Ronny Landsverk on 25 Apr 2017
Commented: Walter Roberson on 17 Dec 2017
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...

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Ronny Landsverk
Ronny Landsverk on 25 Apr 2017
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
Jan on 25 Apr 2017
Does it shed any light to your problem that \r\n is the standard DOS line break?
Ronny Landsverk
Ronny Landsverk on 25 Apr 2017
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 ?

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Accepted Answer

Jan
Jan on 25 Apr 2017
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.

  3 Comments

Ronny Landsverk
Ronny Landsverk on 25 Apr 2017
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
ali on 17 Dec 2017
I have a same problem, how to use new line???
Walter Roberson
Walter Roberson on 17 Dec 2017
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.

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More Answers (2)

Walter Roberson
Walter Roberson on 26 Apr 2017
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.

Mohamed Abdelhamid
Mohamed Abdelhamid on 7 May 2017
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.

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