MATLAB Help: "Unknown Mex argument '-o'" [duplicate] - matlab

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mex with MATLAB2013a Unrecognized switch: -o
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Closed 7 years ago.
I'm trying to run the Deformable Parts Model MATLAB code provided here and I keep getting this error when running the demo.m file. The specific lines it hangs up on are:
eval([mexcmd ' gdetect/fconvsse.cc -o fconv']);
and
eval([mexcmd ' gdetect/fconv_var_dim_MT.cc -o fconv_var_dim']);
This is a pretty popular tool for detection (cited thousands of times in subsequent papers), so it's certainly not the code itself. I'm running it on MATLAB R2014a on CentOS 6.5. The documentation does say:
The software was tested on several versions of Linux and Mac OS X using MATLAB version R2011a. Earlier versions of MATLAB should also work, though there may be compatibility issues with releases prior to 2009."
Generally R2014a runs stuff from older versions though. Does anyone know what I can do to fix this? Or at least what the '-o' command even refers to? I checked the source code being compiled but couldn't find a parser or anything.

Answer 1

That's probably because there is no such thing as -o flag. However, there is a CAPITAL O flag, so -O. That stands for optimizing the code so that you get the best running code given what you have coded. However, this is already enabled by default, but there is an -output flag. This is probably more along the lines of what you need, judging from the way mex is getting called. -output allows you to override how the output MEX file would be named instead of assuming the name of the MEX implementation file that is being compiled.... so in your case, that would be fconvsse or fconv_var_dim_MT.
As another recommendation, I would also recommend you enable verbose mode so you can see everything that is happening under the hood while the code is being compiled. That is enabled by the -v flag.
Therefore, do this:
eval([mexcmd ' -v gdetect/fconvsse.cc -output fconv']);
and:
eval([mexcmd ' -v gdetect/fconv_var_dim_MT.cc -output fconv_var_dim']);
For more help on mex compilation flags, see the help page: http://www.mathworks.com/help/matlab/ref/mex.html