How do I call/use the MATLAB engine from a Fortran program?

I'm struggling to get my Fortran code to use the MATLAB engine and run MATLAB scripts/function. I'm using MacOS, gfortran compiler and MATLAB 2019a.

I found an online resource (MATLAB API Guide v5) that describes how to compile the Fortran code:

f77 <include dir> –o <result> <source> <libdir> <libraries>

where:

• <include dir> is –I<matlabroot>/extern/include
• <result> is the name of the resulting program
• <source> is the list of source files
• <libdir> is –L<matlabroot>/extern/lib/$ARCH (in my case, I'm assuming $ARCH = maci64)
• <libraries> is –leng –lmx

which does not work for me.

I have added example code samples for MATLAB (saved as testMe.m), Fortran (shortened without error checks and saved as callMat.f90) as well as the complie command:

MATLAB CODE:

a=2;b=3;c=55;d=42;
fprinft("%2.0f + %2.0f = %2.0f", a, c, (a+c));
fprinft("%2.0f x %2.0f = %2.0f", b, d, (b*d));

FORTRAN CODE:

program callMat
    #include "engine.h" !not sure if this belongs in/before 'program' or exclude entirely (I've tried all 3 versions).
    implicit none
    ep = engOpen('matlab ')
    engEvalString(ep, 'testMe')
    engClose(ep)
end program callMat

GFORTRAN COMPILE COMMAND:

gfortran -I /Applications/MATLAB_R2019a.app/extern/include -o callMat callMat.f90 -L /Applications/MATLAB_R2019a.app/extern/lib/maci64 -leng -lmx

Please could you let me know where I went wrong as I cant even get the example code 'fengdemo.F' working.

Answer 1

[Nipun Katyal]

In order to check if your installation is correct, please follow the steps given in the link below

https://www.mathworks.com/matlabcentral/answers/338303-how-to-set-up-mex-with-gfortran-on-mac

f77 <include dir> –o <result> <source> <libdir> <libraries>

where:

• <include dir> is –I<matlabroot>/extern/include
• <result> is the name of the resulting program
• <source> is the list of source files
• <libdir> is –L<matlabroot>/extern/lib/$ARCH (in my case, I'm assuming $ARCH = maci64)
• <libraries> is –leng –lmx

These steps are for linux os and might not work as you expect them to

since the engine is not present on mac os.

You can compile your fortran file using mex -client engine Filename.F to compile standalone matlab engine applications.

[mary]

I tried to follow the example above to see how a Matlab function can be called in a Fotran code. I am using Linux. I copied "engine.h" from /usr/local/MATLAB/R2021a/extern/include/

I changed the include dir and libdir based on my system. So, I executed the following line in terminal:

gfortran -I /usr/local/MATLAB/R2021a/extern/include -o callMat callMat.f90 -L /usr/local/MATLAB/R2021a/extern/lib/glnxa64 -leng -lmx

And I have following errors:

callMat.f90:5:4:

engEvalString(ep, 'testMe')

1

Error: Unclassifiable statement at (1)

callMat.f90:6:4:

engClose(ep)

1

Error: Unclassifiable statement at (1)

callMat.f90:4:6:

ep = engOpen('matlab ')

1

Error: Symbol ‘ep’ at (1) has no IMPLICIT type

callMat.f90:4:9:

ep = engOpen('matlab ')

1

Error: Function ‘engopen’ at (1) has no IMPLICIT type

Could you please tell me what should be changed in order to make callMat work?