Declaration and addressing of Varying Density Arrays and structures

Abstract

In current higher level languages arrays are parallelepiped in N dimensions, each dimension having an index range from a lower limit to an upper limit (both must be integers), the increment between valid index values being one.By removing the r e s t r i ction of limits and increments to be integers or unity, a homogenously addressed sections or t e a s of an array is defined. Co~.~ining several of these regions each with its own limits and increments but with com~non addressin~forms an array with varying data density.These new arrays are referred to as Varying Density Arrays (VDA).All data elements of a given region are restricted to a single format and structure.The element structure and format of one region in no way restricts elements in other regions. This generalization permits uniform addressing of conventional arrays, VDAs and PL/I or COBOL structures. This paper discusses (i) the concept of a VDA, (2) extensions to PL/I declarations to allow the definition of VDAs, (3) gives examples in PL/I and APL and discusses operations of VDAS and their subarrays.The paper touches on, but does not discuss, mappings to physical storage.

An information indexing taxonomy and the image data type

“…While substantive backing exists for the definition of image data as a fundamental data type [20], [36], [39], [4], [37], empirical studies using image data and image processing systems is largely missing in the academic arena. This is due in part to the lead role which practitioners have taken in imaging technology, which has been the basis for image technology development while scientific research has lagged behind.…”