What do you really need in Julia on the drone? You might be interested in the branch of Julia I'm maintaining, in https://github.com/ScottPJones/julia/tree/spj/lite, where I've attempted to cut out as much as possible from Base, while still having a useful version of Julia. (I've been building it for my Raspberry Pi 2 (Model B)). I've made it so that you should be able to select what parts you want included, simply by adding flags in Make.user.
It does save a substantial amount of memory / resources. On Sunday, February 7, 2016 at 1:50:55 AM UTC-5, Jeff Waller wrote: > > An update: > > It turns out that the default linux client compiled for ARM does work > with a few modifications > <https://gist.github.com/waTeim/0dd3ce0e0d3a3cd1c734>. It is indeed > slow to JIT-compile, (on the order of seconds), but is fast after that. > See randomMatrix.txt in the gist, for > exact measures, but for example rand(100,100) takes 1 second the first > time and then 0.0005 seconds subsequently -- > that's quite a speedup. Likewise, svd of that 100x100 random matrix is 3 > seconds and then 0.05 seconds > afterwards. > > Also, of course, I tried using node-julia and that was difficult, but I > managed to get that working too. Firstly, I had > to add -march=armv7-a to the compile step to allow use of C++ std::thread > to be successful; apparently this > is a known <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65255> bug of > openembedded <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65255>, and > not an issue with Julia. However, I also had to add -lgfortran and > -lopenblas > to the link step to satisfy the loader which is reminiscent of the error > I had > <https://groups.google.com/forum/#!searchin/julia-users/could$20not$20load$20library$20%22libopenblas/julia-users/A8HwlmldVTM/vuU9eNH6ZpAJ> > > when I first tried to get thigs working on > linux in 2014. This is not the same thing but feels possibly related. I > also had to create a symbolic link for gfortran > as only the specialized version (libgfortran.so.3) existed; ln -s > libgfortran.so.3 libgfortran.so; that should probably > be fixed. > > All but 3 of the node-julia regressions worked once I increased the > default timeout time. You can see the relative > speed differences between an OS/X labtop and the drone in the gist as > well. Some of the timings are comparable, > some are not. > > I believe the large difference in time is due to not only the processor > being slower, but the (flash) filesystem as well. > Exec-ing processes on this drone takes a very large amount of time > (relative to normal laptops/desktops). The memory > is limited too (512 MB), so you really have to be careful about resources. > >
