Introduction

This supporting library was written by hal clark over the span of many years (2010-2024) to house bits of code that are convenient for multiple projects.

Most, but not all of Ygor's routines are focused on scientific or mathematic applications (i.e., geometry, simulation, optimization, and statistics). The routines in this library were all developed for specific projects with specific needs, but which may (have) become useful for other projects. Ygor's routines will grow, be replaced, be updated, and may even disappear when their functionality is superceded by new features in the language/better libraries/etc. Neither API nor ABI stability is guaranteed.

This library is meant to be 'ugly' -- it houses a ragtag bunch of routines that would otherwise pollute other projects and be duplicated multiple times. The focus is on providing functionality rather than optimizing the interface, speed, or beauty. Additions of new generic routines is welcomed so long as there is some reasonable chance they will be applicable or broadly useful.

License and Copying

All materials herein which may be copywrited, where applicable, are. Copyright 2010-2024 Hal Clark. See LICENSE.txt for details about the license. Informally, Ygor is available under a GPLv3 license.

All liability is herefore disclaimed. The person(s) who use this source and/or software do so strictly under their own volition. They assume all associated liability for use and misuse, including but not limited to damages, harm, injury, and death which may result, including but not limited to that arising from unforeseen or unanticipated implementation defects.

Project Home

The Ygor homepage can be found at http://www.halclark.ca/. Source code is available at https://gitlab.com/hdeanclark/Ygor/ and https://github.com/hdclark/Ygor/.

Dependencies

See PKGBUILD for a up-to-date list of dependencies. As of writing, various bits of Ygor rely on:

• STL/C++17: heavily, throughout; mostly C++11 but some C++14 and C++17.
• Boost: various.
• Eigen: a few YgorMath routines, optionally.
• spookyhash: YgorAlgorithms. Very little - one function at time of writing.
• GNU Scientific Library: YgorStats and YgorMathBasisSplines.
• GNU plotutils: YgorPlot. Weakly - via shell/pipe.
• Gnuplot: YgorPlot. Weakly - via shell/pipe.

All dependencies can be optionally disabled, though this will result in loss of functionality.

Installation

This project uses CMake. Use the usual commands to compile:

$>  cd /path/to/source/directory
$>  mkdir build && cd build/

Then, iff by-passing your package manager:

$>  cmake ../ -DCMAKE_INSTALL_PREFIX=/usr
$>  make && sudo make install

or, if building for Debian:

$>  cmake ../ -DCMAKE_INSTALL_PREFIX=/usr
$>  make && make package
$>  sudo apt install -f ./*.deb

or, if building for Arch Linux:

$>  rsync -aC --exclude build ../ ./
$>  makepkg --syncdeps --noconfirm # Optionally also [--install].

A helper script that will auto-detect the system and package or install properly can be invoked as:

$>  ./compile_and_install.sh

Known Issues

• The Gnuplot async plotter will cause the main thread to hang on some systems. It can be made to block instead, but this is hard-coded at the moment. The core issue appears to be communicating via pipes with Gnuplot rather than via a proper API.

Rough Historical Timeline

• May/June 2012

  • Routines from some ad-hoc common 'convenience' headers were amalgamated into this project. The conversion to a set of linkable and/or header-only sources was started.

• Sept 2012

  • Some routines have gradually been modified or added as needed. The inclusion of a binaries directory is designed to expose some library functions to the shell. It has been difficult to keep the library free of external dependencies.

• May 2013

  • Development in the library has waned somewhat due to functionality existing for most of my current use-cases. I haven't bought into unit tests nor version control yet. Currently, I'm interested in cleaning and curating what I've got to provide as solid a base as possible for future addition.

• June 2013

  • Renamed library from 'Project - Utilities' and 'MyUtils' to 'Project - Ygor' in order to release it. Haven't had a chance yet because of ongoing thesis work. It'll have to wait until afterward.

• July 2013

  • Lately, library development has mostly focused on minor additions, refactoring, and addition of extra error handling for easier use. I expect development to pick up a little after the thesis. Specifically, I'd like to focus on code quality. It mostly seems to work (I don't often encounter bugs), but there are major irritants like non-standard error handling/signalling, naming conventions all over the place, and huge files which should be broken up into smaller pieces (or several books :) ).

• Aug 2013

  • Small additions, mostly elaborations of existing routines. Major additions include parametric fitting (partial migration from Project - PolyCAS) and some statistical routines for p-values. The latter introduce a GSL dependency. I hope to implement my own beta functions to get rid of it ASAP ... but the GSL isn't such a bad dependency. It is nice to have quality code publically available.

• Apr 2014

  • Cleanup effort underway. I've tried to fix inconsistent naming schemes, performed static analysis to find any bugs which haven't yet been found, shuffled code around -- either into more specific files or namespaces, and tried to use more consistently handle function behaviour arguments and error signaling. I've also spent some time thinking about a better unit testing scheme. This was a big undertaking!

• July 2016

  • Migrated code and limited history (~late 2015) to git to ease deployment. Some clean-up of junk files was performed. Still relying on GNU Make(files), and the project hierarchy is a bit of a mess. Modernization is planned.

• March 2017

  • Migrated to CMake. Removed a few small extraneous files, but the repo needs a good clean. The code also needs to be modernized and warnings dealt with.

• April 2017

  • Made sources publically available on GitHub and GitLab at [https://gitlab.com/hdeanclark/Ygor] and [https://github.com/hdclark/Ygor].

• April 2019

  • Added integration with static analysis tools and rudimentary CI tooling.

• January 2020

  • Added support for writing many types of mesh file formats (obj, off, stl) over the last few months. Limited reading support since some of the formats are fairly open-ended.

• February 2020

  • Improved 3D voxel lookup efficiency for regular images via the planar_image_adjacency routine.

• March 2020

  • Added faster projection-based is_point_in_poly sub-routine to generic Mutate_Voxels interface routine.
  • Revisited test cases, ensuring they all build.

• April 2020

  • Added generic TAR file read and write support. Small clean-up primarily in math and image files.

• May 2020

  • Started writing unit tests in earnest for core math components focusing on basic usage and edge behaviour (e.g., handling non-finite data).
  • Added basic Affine transformation class.

• June 2020

  • Added bare-bones arbitrary-dimension matrix class to provide 'polyfill' for when external libraries may not be available, to ensure a means of passing matrices across library interface with a stable API (and ABI, if needed), and as a means of controlling serializability.

• August 2020

  • Expanded testing, added CI build-and-test, and increased static analysis.
  • Re-wrote a few routines to use more modern features to improve portability. The port is not comprehensive, but Ygor can now be compiled with MXE.

• October 2020

  • Encircle_Images: provide default enum class.
  • contour_collection: added metadata selector.
  • Document release DOI.

• November 2020

  • Overhauled XYZ, OBJ, and OFF file IO readers to be less stringent when reading point sets.
  • Point sets gained support for normals.
  • Added unbiased surface mesh random sampler. This can be used for Monte Carlo surface sampling.
  • Factored surface mesh garbage collection into a single cleanup routine.
  • Only link libstdc++fs if it is present.

• December 2020

  • Added basic ASCII PLY read and write support for surface meshes.
  • Added vec2 and vec3 layout checks and cast operators to and from std::array.
  • Support for Boost::Serialization 1.74 and earlier versions.
  • Created endian-aware binary IO routines.
  • Added binary PLY support.
  • Improved test portability by removing non-standard math constants (e.g., M_PI).
  • Added minimal support for vertex colour and vertex normals to point clouds and surface meshes, as well as for OBJ, OFF, and PLY IO (where applicable). Still not yet fully supported for all formats.
  • Improved interoperability between point clouds and surface meshe.
  • Added 'standard' 32 bit RGBA packing routine for point clouds and surface meshes.

• January 2021

  • PLY: increase portability and prefer signed ints for face vert indices.
  • Added common affine transformation factory functions.
  • Added cast conversions between affine transform and num array classes.

• February 2021

  • Added 3D convex hull extractor. Used an incremental algorithm, but at the moment the algorithm cannot be resumed. Scaling is reasonable; at the moment vertices do not need to be fully loaded into memory, but random access is needed. (Support for non-random access iterators is supported, but only recommended for a small number of vertices.)

• June 2021

  • Mutate_Voxels: handle degenerate contour geometry better.
  • Mutate_Voxels: provide user access to contour overlap mask.
  • Mutate_Voxels: provide type alias for user-provided functors.

• August 2021

  • YgorTime: remove FUNCERR, add regex-based stringified date-time parsing, and provide fractional seconds, if available.
  • YgorString: add GetAllRegex2 variant that accepts a precompiled regex.
  • PLY: support obj_info statement.

• September 2021

  • YgorArguments: add extra-safe workaround and reference, and capture local copy of key.
  • Arm: avoid clobbering user-provided march, mcpu, and mtune flags.
  • YgorArguments: rewrite argument parser, use feature-test macros specified in man page.
  • YgorTime: add minimal test cases for IO.

• October 2021

  • YgorImages: added double-double type instantiations.
  • Planar_adjacency: added min/max index query.

• March 2022

  • ConvexHull: add eps margin for visibility estimation.
  • Bug fix: replace numeric_limits::min --> lowest.
  • affine_transform: make read and write symmetric, and provide a stream input constructor.
  • Provide base64-aware key-value pair encoder/decoder routines.
  • Add ::invert() to affine_transform and up to 4x4 for num_array.
  • Expand_Macros: add shell-like bracket support for controlling macro scope.

• April 2022

  • simplify_inner_triangles: add local non-manifold edge check, consolidate warning messages, add a few unit tests, add more stringent checks, reject candidate faces with negative orientation, add extra check of face reduction, and honour transaction semantics.
  • Provide fallback for git CVE-2022-24765.
  • fv_surface_mesh: add flat surface vertex removal.
  • ConvexHull: replace face vector with map, prescan for large seed tet and more precisely update face adjacency, and revert to exact visibility testing.

• May 2022

  • YgorImages: added note about row-major indexing.
  • YgorTAR: add cstring header for std::memcpy.

• June 2022

  • Added yspan<>, a non-owning span-like container that supports stride with arrays of composite objects.
  • FITS images: update support for FITSv4.0 spec, and imbue FITS reader and writer with support for arbitrary key-value metadata.
  • FITS images: replaced single-image reader and writer with multi-image reader and writer using the FITSv4.0 IMAGE extension.