Software & CompSci
Papers

Synchronizing Many Filesystems in Near Linear Time
By Elod Csirmaz and
Laszlo Csirmaz, in
Future Internet 2023; 15(6):198.
Finding a provably correct subquadratic synchronization algorithm for
many filesystem replicas is
one of the main theoretical problems in Operational Transformation (OT) and
Conflictfree Replicated Data Types (CRDT) frameworks.
Based on the Algebraic Theory of Filesystems, which incorporates
noncommutative filesystem commands natively, we developed and built a
proofofconcept implementation of an algorithm which synchronizes an arbitrary
number of replicas. It is provably correct,
and has linear complexity after an initial
sorting phase. It works by
identifying conflicting command pairs and requesting one of them to be
removed; can be guided to reach any of the theoretically possible synchronized
states.
Also available on
arXiv ».
See sample implementation of
the filesystem synchronization algorithms on GitHub »

Data Synchronization: A Complete Theoretical Solution for
Filesystems
By Elod Csirmaz and
Laszlo Csirmaz, in
Future Internet 2022; 14(11):344.
Data reconciliation in general, and filesystem synchronization in particular, lacks rigorous
theoretical foundation. This paper presents, for the first time, a complete analysis of synchronization
for two replicas of a theoretical filesystem.
While existing synchronizers are operation
based as they define, using some rationale or heuristics, how conflicts are to be resolved without
considering the effect of the resolution on subsequent conflicts, our approach is declaration
based: we define what constitutes the resolution of all conflicts, and
we prove the existence of sequences of commands which convert the replicas into a common
synchronized state.
All possible synchronized states are described by
a partial order on the conflicts describing the order in which they need to be resolved,
as well as the effect of each decision on subsequent conflicts. Using this classification, the outcomes
of different conflict resolution policies can be investigated easily.
Also available on
arXiv »

Algebra of Data Reconciliation
By Elod Csirmaz and
Laszlo Csirmaz, in
Studia Scientiarum Mathematicarum Hungarica (26 Sep 2022).
A paper on the algebra of data synchronisation which contains stronger and more rigorous results than before,
and extends their scope to more data types.
We investigate the algebraic properties of filesystem command sequence pairs that are applicable to the same data structure,
and use these results to show that the reconciliation problem has a unique maximal solution.
The syntactical properties of this solution also allow for an efficient algorithm to produce it.
Also available on
arXiv »

Interpreting Neural Networks by Reducing Nonlinearities during Training
A short paper and sample code demonstrating a simple solution that makes it possible
to extract rules from a neural network that employs Parametric Rectified Linear Units (PReLUs).
We introduce a force, applied in parallel to backpropagation,
that aims to reduce PReLUs into the identity function, which then causes the neural network
to collapse into a smaller system of linear functions and inequalities suitable for
review or use by human decision makers.
Read the paper »
More on GitHub »


Algebraic File Synchronization: Adequacy and Completeness
In this paper we investigate file synchronization. We define algorithms for update detection and reconciliation
over an algebraic system of filesystem operations with high information content,
and present rigorous proofs that they work as intended and cannot be improved on.
Available on arXiv.org.
More »

An Algebraic Approach to File Synchronization
Norman Ramsey and Előd Csirmaz, “An Algebraic Approach to File Synchronization,”
in
Proceedings of the Joint 8th European Software Engineering Conference and
9th ACM SIGSOFT Symposium on the Foundations of Software Engineering
(New York: ACM Press, 2001), 175–185.
More »

A Transmission Protocol over the LP Port
László Csirmaz and
Elod Csirmaz,
“
Egy kommunikációs protokoll [A Transmission Protocol over the LP port],”
in Híradástechnika
2003/03,
42–
46.
We present and test a communication protocol using the line printer port with automatic synchronisation
where bits or trits are transmitted as state changes.
More »
Software

Superloop: Complex RNN Models
A "superloop" is an extra loop that connects the output of a recursive neural network (RNN)
back to its input in the next timestep via one or more external
systems.
This project contains:
a framework to build RNNs with a superloop in TensorFlow/Keras,
an implementation of a simple gated recurrent unit,
an implementation of a registerbased memory unit,
and an implementation of an attention system that allows the network to move freely along the input
data.
More »

Trainable Online Clustering
Exploring recognizing unseen clusters with a neural network.
Given an initial, labeled batch of data, we aim to train a system
that is capable of classifying a stream of data and recognizing new classes
it has not yet seen.
More and get the code »

PHP_Beautifier filters
Filters for PHP_Beautifier that
keep empty lines in the source,
break argument lists and arrays
into multiple lines, or change how assignment operators are spaced.


ESFS
A filesystem in C based on FUSE that supports snapshots.
More »
More projects

openscadpy
is a Python OOP precompiler for OpenSCAD's language.

nn_rnd_training
trains neural nets using smart random walk without backpropagation (TensorFlow).

Manatee
checks whether the expected values (means) of two samples are significantly different using bootstrapping.

ComfySQL
is a PHP convenience class for MySQL databases.

SQLBrite
is a PHP convenience class for SQLite3 access.
Earlier projects
Some old pieces of software for MSDOS systems
Use the
DosBox emulator to run these applications

Solit: classic solitaire
 Includes hints; has an autoplay function; games can be restarted and reloaded
 Download the executable:
solit.exe
 Read the
documentation
 Get the source on
GitHub

