Error during loading input

Dear Fluka Experts,

please excuse such a basic question. As part of my master’s thesis, I am supposed to simulate a radioactive source. Unfortunately, I am still a complete beginner and find it very difficult to get along with the simulation program (my Fluka version is: 3.1-15.1). Therefore I wanted to work through the files from the 2 week course from 2021 and load the 2 example files (example.inp and geometry-exercise-basic-editing.inp) to try something out. This is where the problem comes up: When I go to the “Input” tab to load in a .inp file, I get the error message:

"warning during loading: Error or warning messages appeared while loading input. Open the output window for more information.

In the output window then the error message is:
“>e> ERROR: Cannot open file ‘/home/…inp’ for reading”.

If I create an input myself, save it and later reload it, it works without problems (the sample files and my self-created files are in the same location and are both “.inp”).

Now I am afraid that I made a mistake during the installation or that later, when I finally have a good result for my master thesis, I might have big problems. Also, unfortunately I can’t practice on the sample files to understand the program better.

I would be very grateful if you can help me. Thank you very much in advance.

Dear @LePink ,

could you try to open the input files from the command line, with the command

flair example.inp

and let us know it it works this way?


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Thank you for the quick reply.
I hope I understood it correctly. I typed in Ubuntu instead of “flair” as usual, this time “flair example.inp”. Unfortunately I got exactly the same error message as before.


Is the example.inp file in the same directory from where you are running flair?


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Unfortunately, I am not quite sure.
Can you please tell me again how I can tell which directory I am running Flair in?

I have a folder where all my input files are saved. Inside that folder is another folder called “.flair”. When I open this one, there are 2 files in it. One is a file called “flair” for configuration settings and the other is a “flair.ini” file.

If I remember correctly, I did not get further into subfolders during the installation in Ubuntu and therefore had to save the files like setup_wsl etc. directly under (C:). Could it have something to do with that?

Dear @LePink,

You can type the command pwd in order to see the path and then you need to go to the directory where your .inp file is saved using cd (change directory) until you reach the destination. Take a look at the Sections 3.3.1 and 3.3.2 here.


Hello Fluka experts,

thank you very much for the hints. I found out that my inputs are in a data path that is actually “invisible”. I have them displayed to me with “Show View” (it starts with User\Name\AppData and AppData is actually not accessible). The data path is very long and I don’t remember entering it during the installation in Ubuntu.

Regarding the “pwd” command in Ubuntu, I am a bit confused and not sure if it is the same location/data path. Because when I enter the command “pwd”, the result in Ubuntu is home\name. Here, after all, these 2 data paths match the last two specifications of the above data path (from input)… But is it normal that Ubuntu gives only the last 2 specifications?
Otherwise it might not be the same location after all.

With kind regards.

You can reach that path by using cd /mnt/c/Users/[Name]/AppData

Anyway, I suggest you to move the input files to another location (preferably to another disk) because when you will run the input file FLUKA will create additional files and it’s not recommended to fill the space where your operating system is installed.