Introduction

This is an experimental n-dimensional array implementation in Clojure. Based on ideas from the Blaze project, the Chapele language, the ZPL language and others.

Core Abstractions

These top level abstractions are mainly based off the main abstractions in the Chapele language.

Domain

A Domain represents an index set. Domains are a generalization of the region concept pioneered by the ZPL language. Domains can be named, assigned, and passed between functions. Domains support iteration, intersection, set-oriented queries, and operations for creating other domains. They are also used to declare, slice, and reallocate arrays

A Domain is used to represent each domain value in a program. As such, its main responsibility is to store a representation of the domain’s index set. For layouts and regular domains, the complete index set representation is typically stored directly within the descriptor. For distributions of irregular domains that require O(numIndices) storage to represent the index set, a distribution will typically store only summarizing information in its global descriptor. The representation of the complete index set is spread between its associated local descriptors in order to achieve scalability

DomainMap

A domain map specifies the implementation of the domains and arrays that are mapped using it. That is, it defines how domain indices and array elements are mapped to distributions, how they are stored in memory, and how operations such as accesses, iteration, and slicing are performed. Each domain and array is mapped using some domain map.

Distribution

A distribution abstractly represents a unit of the target architecture that supports processing and storage. On conventional machines, a distribution is typically defined to be a single node, its memory, and its multicore/SMP processors.

Distributions facilitate the storage/retrieval of the actual elements of an array. It is the responsibility of the DomainMap to translate the coordinates of a domain into the low-level storage coordinates of the elements contained in a distribution.

Many implementations of Distributions will also implement the Indexed and Counted protocols for low level access to their elements.

Concept map

Concept	NumPy	Blaze	ZPL	Chapele	x10	R	K	J	APL
Cartesian Coordinate Space	shape tuple	Space & Shape	Region	Domain/IndexSet	Region
Coordinates	x,y… coords	Index			Point
Mapping of coords to storage		Layout		DomainMap
Low Level Storage	buffer	ByteProvider		Locale	Place
Storage Distribution				Distribution

Further Reading

• Blaze (next generation numpy): http://blaze.pydata.org/docs/
• Chapele http://chapel.cray.com/index.html
• x10 http://x10-lang.org/
• Fortress http://en.wikipedia.org/wiki/Fortress_(programming_language)
• ZPL http://www.cs.washington.edu/research/zpl/home/index.html