org-howto/sw/xo.org

xo libraries

• Xo
• Python Libraries
• C++ Libraries
• External Dependencies
• Python Abstraction Tower
• C++ Abstraction Tower
• Size

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Xo

A set of integrated libraries for event-based simulation with stochastic processes. Intended for use in C++ and python applications.

Variety of features covered, for example: kalman filters, stochastic processes, complex event processing, simulation, websockets.

Python Libraries

• xo-pywebsock in-memory http server; can expose entirely-native publishing pipeline via websockets.
• xo-pywebutil lo-level abstractions for http: endpoints, attribute lists.
• xo-pykalmanfilter linear kalman filter with simulation support.
• xo-pymatrix matrix algorithms [wip]
• xo-pydistribution probability distributions e.g. Kolmogorov Smirnov
• xo-pyprocess stochastic processes with simulation focus.
• xo-pyreactor complex event processors + polling reactor.
• xo-pyprintjson plugin json printing for xo c++ classes.
• xo-pyreflect plugin introspection for xo c++ classes.

C++ Libraries

http

• xo-websock in-memory http server with websocket and python support.
• xo-webutil low-level abstractions for http: endpoints, attribute lists.

stochastic processes + friends

• xo-kalmanfilter linear kalman filter with simulation support.
• xo-process stochastic processes and simulation-compatible realizations.
• xo-distribution probability distributions including Kolmogorov-Smirnov
• xo-statistics header-only. online accumulators, histogram.
• xo-randomgen header-only. fast pseudo random number generators. xoshiro**,

complex event processing

• xo-simulator deterministic event-based simulation
• xo-reactor api for complex event processors + simple polling implementation.

data structures

• xo-ordinaltree header-only. fast in-memory B+ tree, red-black tree w/ ordinal statistics.

quantitative

• xo-matrix header-only. specialized matrix algorithms with some vectorization [wip]
• xo-unit header-only. no-alloc constexpr exact unit conversions with some fractional-dimension support.
• xo-ratio header-only. no-alloc constexpr exact ratio arithmetic.

general-purpose

• xo-flatstring header-only. no-alloc plain-old-data constexpr string implementation
• xo-callback header-only. reentrant callback set
• xo-printjson json printer with plugin support.
• xo-reflect reflection/introspection library
• xo-subsys orderly startup and shutdown for subsystems with plugin features
• xo-refcnt intrusive reference counting
• xo-indentlog header-only logging library; colorized output with indentation tracking program call structure

build tools

• xo-cmake cmake modules.

External Dependencies

name	deps
all	gcc, lcov, catch2, cmake
all docs	doxygen, graphvix, sphinx, breathe, sphinx_rtd_theme
all py	pybind11
xo-kalmanfilter	eigen
xo-websock	libwebsockets

Python Abstraction Tower

Each python library pyfoo depends on similarly-named c++ library foo.

     +----------+----------+-----------+-----------+----------+
     |          |          |           | pyprocess | pykalman |
     |          |          |           |           |  -filter |
     | pymatrix | pydistri | pywebsock +-----------+----------+
     |          | -bution  |           |        pyreactor     |
     |          |          |           +-------------+        |
     |          |          |           | pyprintjson |        |
     |          |          +-----------+-------------+--------+
     |          |          | pywebutil |       pyreflect      |
     +----------+----------+-----------+----------------------+

C++ Abstraction Tower

     +--------+--------+---------+-----------+---------+-----------+------------+------------+
     |        |        |         |  process  | kalman  | simulator |            |            |
     |        |        |         |           | -filter |           |            |            |
     | matrix | distri | websock +-----------+---------+-----------+            |            |
     |        |-bution |         |                                 |            |            |
     |        |        |         +---------+      reactor          |            |    unit    |
     |        |        |         |printjson|                       |            |            |
     |        |        +---------+---------+-+-----------+---------+ statistics |            |
     |        |        | webutil |  reflect  |           |         |            |            |
     +--------+--------+---------+-+---------+           | ordinal |            +-------+    |
     |           refcnt            |         |  callback |  tree   |            | ratio |    |
     |                 +-----------+ subsys  |           |         |            +-------+----+
     |                 | indentlog |         |           |         |            | flatstring |
     +-----------------+-----------+---------+-----------+---------+------------+------------+
     |                                  xo cmake modules                                     |
     +---------------------------------------------------------------------------------------+

Size

(per cloc; excludes comments. Sizes as of 10jun2024)

subsystem	cmake	.hpp	.cpp
xo-websock	34	186	1418
xo-webutil	27	77	56
xo-kalmanfilter	47	552	904
xo-process	34	645	163
xo-simulator	31	186	392
xo-reactor	39	1110	261
xo-distribution	24	717
xo-ordinaltree	24	3962
xo-statistics	22	166
xo-matrix	29	1266
xo-unit	49	1972
xo-ratio	36	418
xo-reflect	54	891	289
xo-refcnt	36	306	130
xo-indentlog	35	1632
xo-flatstring	34	582
xo-callback	25	180
xo-subsys	27	153
xo-cmake	1164