Hi,
I am working on converting a CAN logger file that is several hours long. The tools provided by the CAN logger manufacturer can't handle data files this big. So I have just buckled down and done it in Matlab. Basically, because the Vehicle Networking Toolbox reads a dbc file for you which saved me a lot of time.
The problem is that the script runs really slow... after running the profiler on it, it appears that a significant amount of time is used doing the operations to convert the logger data into an engineering number. This includes functions like bin2dec, dec2bin, fliplr.
I start with a line from a logger file such as this:
' 0.000595 1 33 Rx D 8 00 96 17 32 00 00 64 09';
The last 8 numbers are the 8 bytes of the CAN message. I read this into an array called "bytes". This works pretty quickly.
bytes = [0 96 17 32 0 0 64 9]
I then process "bytes" array to get what I call "bitstrm". Just 1's and 0's that I can select and process.
bitstrm = fliplr(dec2bin(typecast(uint8(bytes),'uint64'),64));
Then I run the data through the attached function, "calc_sig_value" that converts it to engineering units. (Would have pasted below but couldn't get code button to work). The function is more or less carrying out this operation.
"engineering value" = calc_sig_value(bitstream,CAN_Message_ID,Signal_index,database_structure)
where database_structure is the output of applying canDatabase() from the vehicle network toolbox to a Vector *.DBC file
My question is this: Based on the process I have detailed so far, am I doing operations to convert this message in an inefficient way that can be easily improved by rearranging the order I call MATLAB functions in? I feel like I am doing a lot of fliplrs, and dec2bin, bin2dec, etc. and probably not in the optimal order. This process does give the correct values, it is just slow.
Let me know if something is unclear... I expect I have left out something major that I am doing. Also, I can't really provide my dbc file, unless I were to sanitize it. Let me know if that really helps with optimizing.
