This is great, and something I wanted to do but hadn't had time for. I'll give it a try when I have a chance.
On Mon, Apr 20, 2015 at 10:22 AM, Jay Kickliter <[email protected]> wrote: > I just pushed a rough draft gr-juliaffi > <https://github.com/JayKickliter/gr-juliaffi> to GitHub. It is not a > Julia package, but a GNU Radio module (C++/Python) that calls your Julia > code to do the actual signal processing. > > If you're not familiar with GNU Radio, it is a software defined radio > (SDR) framework. SDR is really cool. Traditional radio hardware is > dedicated to certain kind of signal (like a satellite modem or FM > receiver). SDR lets you use generic hardware that does little more than > digitize the raw radio waves and send them to a computer. From there, all > the signal processing is performed in software. There are real world > applications > <http://www.fsf.org/blogs/community/free-software-in-space-gnu-radio-and-the-isee-3-spacecraft> > of SDR. I use it almost every day. > > The motivation for this block came recently when I needed something GNU > Radio didn't have yet. At my job, we're developing new 802.15.4 hardware. > There is an 802.15.4 <https://github.com/bastibl/gr-ieee802-15-4.git> > out-of-tree module for GNU Radio, but it's not complete and doesn't have > the capability of de-spreading > <http://en.wikipedia.org/wiki/Direct-sequence_spread_spectrum> 802.15.4 900 > MHz BPSK signals. I wrote code to de-spread the signal in Julia, and piped > from/to GNU Radio using ZeroMQ. That works fine, but it's cumbersome. Why > not just have GNU Radio call the Julia code directly? > > If you do want to use the module, please let me know what issues you run > into when building/using it. I spent two solid days just trying to get > cmake to find and properly set up linking to libjulia. I'm using OS X, and > @rpath was causing the biggest problem for me. It only built when I finally > stopped trying to tell cmake where to find libjulia and switched to > find_library. Also I had to do an actual `make install release` in the > Julia repo for all the headers and libraries to be in predictable > locations. That's because the FindJulia cmake module I added calls julia > on the command line to figure out where stuff is. The code still crashes if > I try to run it with `jl_init(NULL) > <https://github.com/JayKickliter/gr-juliaffi/blob/master/lib/juliablock_ff_impl.cc#L47> > '. > > There's still more c++ work to be done, and I don't know c++. I just > infinite monkey it 'till it works. I just hope I or someone else can figure > out how to make the c++ configure itself dynamically, so it isn't necessary > to define blocks for every combo of input/output type. Most of the repo was > automatically created with gr_modtool. This file > <https://github.com/JayKickliter/gr-juliaffi/blob/master/lib/juliablock_ff_impl.cc> > is pretty much the whole project. It's definitely possible to change the > number of inputs/outputs to block at runtime. Looking at the code, I think > it may be possible to change the type as well. > > I was hoping have this done with some good examples in time to give a > JuliaCon talk. Maybe next year. I'll be there anyway, if anyone's > interested I'll give an informal demo. >
