converting MATLAB code to Fortran [closed]

Question

I a medical researcher with code written in MATLAB 2009b that runs very slowly because of a self-referential loop (not sure of the programming lingo here), i.e., the results of the first iteration is used during the second iteration, etc. (I have vectorized it to a fare-thee-well. I have run the Profiler.)

I'd like to convert the slow parts of the code to a mex function. I learned Fortran in the early 1970s but haven't used it since. The code I need to convert doesn't do anything fancy, it is just a long numerical calculation.

My question is: what would be the easiest-to-relearn version of Fortran adequate for this purpose, and what compiler works best on the Intel Mac for this? I found information comparing syntax in MATLAB to Fortran 90 for example, and the conversion doesn't look like it would be too daunting for me. However, again, I am no programmer.

I am using a MacBook Pro with OS 10.6.

Appreciate any help, thanks.

Answer 1

I'd recommend using modern Fortran, at least 90/95 as the syntax is much more forgiving and almost all compilers now support it.

On a Mac I would recommend gfortran from here. It's not the most recent version, but it's well integrated with Apple build tools (you will need to install Xcode from your Mac OS DVD) and works well. In the numerical python community, which depends a lot of Fortran extensions, this build is highly recommended.

I haven't actually used fortran mex on the mac - but I think it should be fairly straightforward if you follow the mex documentation - and as you say translating code from Matlab to Fortran shouldn't be too bad (it's better if you can avoid calling Matlab functions, but fortran has sensible slicing and array access).