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+Multi-Dimensional Data Structure (mdds)
+=======================================
+A collection of multi-dimensional data structure and indexing 
+algorithm.  
+
+Overview of data structures included in mdds
+--------------------------------------------
+
+This library implements the following data structures:
+
+* segment_tree
+* flat_segment_tree
+* point_quad_tree
+* multi_type_vector
+* multi_type_matrix
+* sorted_string_map
+* trie_map
+* packed_trie_map
+* rtree
+
+### Segment Tree
+
+Segment tree is a balanced-binary-tree based data structure efficient 
+for detecting all intervals (or segments) that contain a given point.  
+The segments may overlap with each other.  The end points of stored 
+segments are not inclusive, that is, when an interval spans from 2 to 
+6, an arbitrary point x within that interval can take a value of 2 <= 
+x < 6.  
+
+### Flat Segment Tree
+
+Flat segment tree is a variant of segment tree that is designed to 
+store a collection of non-overlapping segments.  This structure is 
+efficient when you need to store values associated with 1 dimensional 
+segments that never overlap with each other.  Like segment tree, 
+stored segments' end points are non-inclusive.  
+
+### Point Quad Tree
+
+Point quad tree stores 2-dimensional points and provides an efficient 
+way to query all points within specified rectangular region.  
+
+### Multi Type Vector
+
+Multi-type vector allows storage of unspecified number of types in a single 
+logical array such that contiguous elements of identical type are stored in 
+contiguous segment in memory space. 
+
+### Multi Type Matrix
+
+Multi-type matrix is a matrix structure that allows storage of four different 
+element types: numeric, string, boolean and empty. It uses multi-type vector as 
+its underlying storage. 
+
+### Sorted String Map
+
+Sorted string map is a simple data structure that takes a pre-sorted list of
+key-value pairs that are known at compile time, and allows efficient lookup.
+It does not allocate memory to duplicate its content, as it directly uses the
+pre-sorted list provided by the caller.
+
+### Trie Map
+
+Trie map is an associative container that stores multiple key-value pairs
+where keys are stored in a trie structure to optimize for prefix searches.
+
+### Packed Trie Map
+
+Packed trie map is nearly identical to the trie map counterpart except that
+this one is immutable.  It packs all its content in a contiguous array for
+optimum storage and lookup efficiency.  This implementation is based on the
+paper titled [Tightly Packed Tries: How to Fit Large Models into Memory, and Make them Load Fast, Too](https://www.aclweb.org/anthology/W09-1505/)
+by Ulrich Germann, Eric Joanis, and Samuel Larkin.
+
+### R-tree
+
+[R-tree](https://en.wikipedia.org/wiki/R-tree) is a tree-based data structure
+designed to store multi-dimensional geometric data with bounding boxes and
+provide optimal performance on region- or point-based queries.  The one
+implemented in this library is a variant of R-tree known as
+[R*-tree](https://en.wikipedia.org/wiki/R*_tree).
+
+
+Documentation
+=============
+[Official API documentation](https://mdds.readthedocs.io/en/latest/) for general
+users of the library.
+
+Packages
+========
+
+Please see the [Releases](https://gitlab.com/mdds/mdds/-/releases) page for
+source package downloads.
+
+If you need old packages, please find them [here](OLD-DOWNLOADS.md).
+
+
+Installation
+============
+Please refer to the [CONTRIBUTING.md](CONTRIBUTING.md) file for build and
+installation instructions.
+
+
+License
+=======
+
+mdds is free software. You may copy, distribute, and modify it under
+the terms of the License contained in the file COPYING distributed
+with this package. This license is the same as the MIT/X Consortium
+license.
+
+
+Who uses mdds?
+==============
+
+These are the projects that are known to use mdds.
+
+* [LibreOffice](http://www.libreoffice.org)
+* [Calligra](https://www.calligra.org/)
+* [libetonyek](https://wiki.documentfoundation.org/DLP/Libraries/libetonyek)
+* [ixion](https://gitlab.com/ixion/ixion)
+* [orcus](https://gitlab.com/orcus/orcus)
+
+If you use mdds and would like your project to be included in the above list,
+please let us know.
+