MCNP Problem - Bad character in column 2

In summary, the conversation discusses an error that is caused by using tabs instead of spaces in the input file for a code descended from FORTRAN. Another issue is the need for specific blank lines between cell cards, surface cards, and data/source sections. The speaker suggests using a simple text editor to edit the file and making sure there are no extra blank lines. The other speaker confirms trying to fix the issue but still encountering the same problem.
  • #1
KOKI
4
0
TL;DR Summary
hello , I am getting an error that reads as follows:

1 PX 12.5

bad trouble in imcn in routine ckchar

bad character, probably a control character, in column 2
hello , I am getting an error that reads as follows:
1 PX 12.5
bad trouble in imcn in routine ckchar
bad character, probably a control character, in column 2Cell cards
1 0 1 -2 -7 8 10 -9 imp: n=1
2 0 2 -3 -7 8 10 -9 imp: n=0
3 0 3 -4 -7 8 10 -9 imp: n=1
4 0 4 -5 -7 8 10 -9 imp: n=0
5 0 5 -6 -7 8 10 -9 imp: n=1
6 0 -14 #1 #2 #3 #4 #5 #7 imp: n=0
7 0 -11 -12 13 imp: n=1
8 0 14 imp:n=0c Surface cards
1 PX 12.5
2 PX 15
3 PX 15.05
4 PX 16.05
5 PX 16.1
6 PX 21.1
7 PY 5
8 PY -5
9 PZ 5
10 PZ -5
11 CX 0.5
12 PX 0
13 PX -1
14 SO 30
 
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  • #2
Try attaching your input file, you will need to rename it to add .txt at the end.

How are you editing it? With a simple text editor?

This is usually a formatting char problem.
 
  • #3
bien
 
  • #4
:
 

Attachments

  • beam-stop01.txt
    957 bytes · Views: 101
  • #5
The error is that you are using tabs instead of spaces. This code is descended from things written in the 1970's, on mainframes, in FORTRAN, by physicists. Some aspects are not very flexible.

A second problem is that the gap between the cell cards and the surface cards needs to be a single blank line. The gap between the surface cards and the data/source section also needs a blank line but more may not matter. The extra blank lines in that section may also be fine, without trying it I'm not sure, but normally that is not done.
 
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  • #6
Alex A said:
The error is that you are using tabs instead of spaces. This code is descended from things written in the 1970's, on mainframes, in FORTRAN, by physicists. Some aspects are not very flexible.

A second problem is that the gap between the cell cards and the surface cards needs to be a single blank line. The gap between the surface cards and the data/source section also needs a blank line but more may not matter. The extra blank lines in that section may also be fine, without trying it I'm not sure, but normally that is not done.
I tried but I find the same problem
 
  • #7
KOKI said:
I tried but I find the same problem
What does "tried" mean here? Did you replace the tabs with ordinary space characters? Did you make sure there was exactly one blank line between cells and surfaces, exactly one blank line between surfaces and data, and no other blank lines?
 
  • #8
KOKI said:
I tried but I find the same problem
Sometimes the name of your input file create problems, do not put any space in your input file . such as you can write mcnpcode.txt but you cannot write mcnp code.txt .. The input file that you run dislikes any space between it. And try to make your input file as short as possible. I am a victim of that kind of error .
 

FAQ: MCNP Problem - Bad character in column 2

What does the "Bad character in column 2" error in MCNP mean?

The "Bad character in column 2" error in MCNP typically means that there is an unexpected or invalid character in the second column of your input file. MCNP expects specific formatting for its input files, and any deviation from this can result in errors. This error often occurs due to a misplaced character, an incorrect line continuation, or an unintended space or tab.

How can I identify the source of the "Bad character in column 2" error?

To identify the source of the "Bad character in column 2" error, carefully review the input file, especially the second column of each line. Look for any characters that do not conform to the expected MCNP format. Common issues include misplaced comments, incorrect use of spaces or tabs, and unintended characters. Using a text editor with line numbering can help pinpoint the exact location of the error.

What are common causes of the "Bad character in column 2" error in MCNP input files?

Common causes of the "Bad character in column 2" error in MCNP input files include:

  • Misplaced or extra characters in the second column.
  • Incorrect use of comment symbols (e.g., c or $) or line continuation symbols (&).
  • Unintended spaces or tabs in the second column.
  • Typographical errors or incorrect formatting of input data.

How can I fix the "Bad character in column 2" error in my MCNP input file?

To fix the "Bad character in column 2" error in your MCNP input file, follow these steps:

  • Open the input file in a text editor that displays line numbers and columns.
  • Check the second column of each line for any unexpected or invalid characters.
  • Correct any misplaced characters, inappropriate spaces, or tabs.
  • Ensure that comment and line continuation symbols are correctly placed.
  • Save the file and rerun the MCNP simulation to check if the error is resolved.

Can I use any tools or software to help prevent the "Bad character in column 2" error in MCNP?

Yes, there are several tools and software that can help prevent the "Bad character in column 2" error in MCNP:

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