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#Epiphany Python This is a Python interpreter designed for low memory many core chips such as the Epiphany co-processor and supports the writing of parallel codes for these architectures. The interpreter and runtime resident in the memory of the actual core is only 24Kb, with the remainder of core memory available for the user's byte code and data. This 24Kb implementation is standalone which means that ePython works both with many core processors executing independently and those working as co-processors with some extra shared memory between the host. Hence ePython is specifically designed to be a very small, tight implementation of the imperative aspects of Python with extensions (via Python modules) for parallelism such as messaging, task farming, interoperability with a full Python interpreter (such as CPython) running on the host and many other features. ePython also supports full memory management and garbage collection.

ePython has been developed by Nick Brown and is licenced under BSD-2.

##Installation Type make If you wish to install it (into the bin directory) then sudo make install followed by starting a new bash session (execute bash at the command line.)

If you do not install it then you can still run epython from the current directory, as ./epython.sh but ensure that epython-device.elf is in the current directory when you run the interpreter. The epython.sh script will detect whether to run as sudo (earlier versions of the parallella OS) or not (later versions.)

In order to include files (required for parallel functions) you must either run your Python codes in the same directory as the executables (and the modules directory) and/or export the PYTHONPATH environment variable to point to the modules directory. When including files, by default ePython will search in the current directory, any subdirectory called modules and then the PYTHONPATH variable, which follows the same syntax as the PATH variable.

Issuing export export PYTHONPATH=$PYTHONPATH:pwd in the epython directory will set this to point to the current directory. You can also modify your ~/.bashrc file to contain a similiar command.

For more information about installing ePython refer here, for upgrading ePython refer here

##Hello world Create a file called hello, then put in the lines print "Hello world"

save it, and execute epython hello (or ./epython.sh hello if you have not done make install.)

Each core will display the Hello world message to the screen along with their core id

For more information about first steps with ePython refer here, for more advanced ePython usage then follow the tutorials in the docs directory which cover writing parallel Python code on the Epiphany.

##Troubleshooting

Often these are set by default, but if it complains that it can not find e-gcc or the libraries, then you will need to set these environment variables:

export PATH=/opt/adapteva/esdk/tools/e-gnu/bin:$PATH export EPIPHANY_HOME=/opt/adapteva/esdk

(you might want to place this in your .bashrc file)

##64 cores

ePython has been developed and tested on a 16 core Epiphany machine, if you have a 64 core chip machine then it should work (still on 16 cores), and it should be trivial to edit the source and linker script to support the full 64 cores.

##Rebuilding the parser/lexer To rebuild the parser and lexer too, then execute make full

##SREC and ELF

The device executable is built in both SREC and ELF format, as of 2016 the loading of SREC on the Epiphany is deprecated and will be removed from later SDK releases. You can choose which to load via the -elf and -srec command line arguments. ELF is the default for ePython, apart from very old Epiphany SDK versions which support SREC.