Lava 0.2.0

Lava 0.2.0 includes several improvements to the Lava Runtime. One of them improves the performance of the underlying message passing framework by over 10x on CPU. We also added new floating-point and Loihi fixed-point PyProcessModels for LIF and DENSE Processes as well as a new CONV Process. In addition, Lava now supports remote memory access between Processes via RefPorts which allows Processes to reconfigure other Processes. Finally, we added/updated several new tutorials to address all these new features.

Features and Improvements

• Refactored Runtime and RuntimeService to separate the MessagePassingBackend from the Runtime and RuntimeService itself into its own standalone module. This will allow implementing and comparing the performance of other implementations for channel-based communication and also will enable true multi-node scaling beyond the capabilities of the Python multiprocessing module (PR #29)
• Enhanced execution performance by removing busy waits in the Runtime and RuntimeService (Issue #36 & PR #87)
• Enabled compiler and runtime support for RefPorts which allows remote memory access between Lava processes such that one process can reconfigure another process at runtime. Also, remote-memory access is based on channel-based message passing but can lead to side effects and should therefore be used with caution. See Remote Memory Access tutorial for how RefPorts can be used (Issue #43 & PR #46).
• Implemented a first prototype of a Monitor Process. A Monitor provides a user interface to probe Vars and OutPorts of other Processes and records their evolution over time in a time series for post-processing. The current Monitor prototype is limited in that it can only probe a single Var or OutPort per Process. (Issue #74 & PR #80). This limitation will be addressed in the next release.
• Added floating point and Loihi-fixed point PyProcessModels for LIF and connection processes like DENSE and CONV. See issue #40 for more details.
• Added an in-depth tutorial on connecting processes (PR #105)
• Added an in-depth tutorial on remote memory access (PR #99)
• Added an in-depth tutorial on hierarchical Processes and SubProcessModels ()

Bug Fixes and Other Changes

• Fixed a bug in get/set Var to enable get/set of floating-point values (Issue #44)
• Fixed install instructions (setting PYTHONPATH) (Issue #45)
• Fixed code example in documentation (Issue #62)
• Fixed and added missing license information (Issue #41 & Issue #63)
• Added unit tests for merging and branching In-/OutPorts (PR #106)

Known Issues

• No support for Intel Loihi yet.
• Channel-based Process communication via CSP channels implemented with Python multiprocessing improved significantly by >30x . However, more improvement is still needed to reduce the overhead from inter-process communication in implementing CSP channels in SW and to get closer to native execution speeds of similar implementations without CSP channel overhead.
• Errors from remote system processes like PyProcessModels or the PyRuntimeService are currently not thrown to the user system process. This makes debugging of parallel processes hard. We are working on propagating exceptions thrown in remote processes to the user.
• Virtual ports for reshaping and concatenation are not supported yet.
• A single Monitor process cannot monitor more than one Var/InPort of single process, i.e., multi-var probing with single Monitor process is not supported yet.
• Still limited API documentation.
• Non-blocking execution mode not yet supported. Thus Runtime.pause() and Runtime.wait() do not work yet.

What's Changed

• Remove unused channel_utils by @mgkwill in #37
• Refactor Message Infrastructure by @joyeshmishra in #29
• Fixed copyright in BSD-3 LICENSE files by @mathisrichter in #42
• Fixed PYTHONPATH installation instructions after directory restructure of core lava repo by @drager-intel in #48
• Add missing license in utils folder by @Tobias-Fischer in #58
• Add auto Runtime.stop() by @mgkwill in #38
• Enablement of RefPort to Var/VarPort connections by @PhilippPlank in #46
• Support float data type for get/set value of Var by @PhilippPlank in #69
• Disable non-blocking execution by @PhilippPlank in #67
• LIF ProcessModels: Floating and fixed point: PR attempt #2 by @srrisbud in #70
• Fixed bug in README.md example code by @mathisrichter in #61
• PyInPort: probe() implementation by @gkarray in #77
• Performance improvements by @harryliu-intel in #87
• Clean up of explicit namespace declaration by @bamsumit in #98
• Enabling monitoring/probing of Vars and OutPorts of processes with Monitor Process by @elvinhajizada in #80
• Conv Process Implementation by @bamsumit in #73
• Move tutorials to root directory of the repo by @bamsumit in #102
• Tutorial for shared memory access (RefPorts) by @PhilippPlank in #99
• Move tutorial07 by @PhilippPlank in #107
• Added Unit tests for branching/merging of IO ports by @PhilippPlank in #106
• Connection tutorial finished by @PhilippPlank in #105
• Fix for issue #109, Monitor unit test failing non-deterministically by @mathisrichter in #110
• Created floating pt and bit accurate Dense ProcModels + unit tests. Fixes issues #100 and #111. by @drager-intel in #112
• Update test_io_ports.py by @PhilippPlank in #113
• Fix README.md Example Code by @mgkwill in #94
• Added empty list attribute tags to AbstractProcessModel by @srrisbud in #96
• Lava 0.2.0 by @mgkwill in #117

New Contributors

• @joyeshmishra made their first contribution in #29
• @drager-intel made their first contribution in #48
• @Tobias-Fischer made their first contribution in #58
• @PhilippPlank made their first contribution in #46
• @gkarray made their first contribution in #77
• @harryliu-intel made their first contribution in #87
• @bamsumit made their first contribution in #98
• @elvinhajizada made their first contribution in #80

Full Changelog: v0.1.1...v0.2.0