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I don't get the meaning of the sign <<>> and also from which line the error is coming as I have a program of more than 30 lines with many defined functions without using "Module" . Is not there any way to display line numbers in Mathematica so that we can know from which line error is coming?


marked as duplicate by Mr.Wizard May 23 '15 at 10:51

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  • $\begingroup$ Mathematica is not so hot on lines and debuggging is not straightforward. Please add the offending code (or a minimal working example thereof) - without code there is no way to help you. $\endgroup$ – Yves Klett May 14 '14 at 16:02
  • $\begingroup$ We need a minimal example to give a clear analysis of the problem, but the cause is likely to be very similar to this: (11982) $\endgroup$ – Mr.Wizard May 14 '14 at 17:02
  • $\begingroup$ I didn't write Quit[] at the end of the program. That is why for the first time when I run the program I got the result, but after some modification when I run the program, I got that error message. Thanks for the help. $\endgroup$ – user22180 May 14 '14 at 19:24

<< ..>> is called a Skeleton. It is is used to show you an abbreviated version of the actual offending line. You can find it in Short and Shallow.

Short[(x + y)^30 // Expand]

Mathematica graphics

You can see the skeleton right there in the middle.

The error message probably comes from an illegal construction like:

(a + b)[x_] := 2

SetDelayed::write: Tag Plus in (a+b)[x_] is Protected. >>


I think you used a function and then tried to manually set another value to it. for instance:

fun=3; fun[x_]:=Tan[x]; gives the following error

"SetDelayed::write: "Tag Integer in 3[x_] is Protected"

you are probably doing something very similar.


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