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Matrix/

union.pro

calculate the union between 2 matrices of whole numbers

union Calculation

result = union(a, b)

Return value

tableau

Parameters

a        in required

arrays of positive integers, which need not be sorted. Duplicate elements are ignored, as they have no effect on the result

b        in required

see a

Examples

 IDL> a = [2,4,6,8]
 IDL> b = [6,1,3,2]
 IDL> union(a,b) = [ 1, 2, 3, 4, 6, 8]  ; Elements in either set

    

Version history

Version

$Id: union.pro 325 2007-12-06 10:04:53Z pinsard $

History

Known issues

Restrictions

The empty set is denoted by an array with the first element equal to -1. These functions will not be efficient on sparse sets with wide ranges, as they trade memory for efficiency. The
HISTOGRAM function is used, which creates arrays of size equal to the range of the resulting set.

 


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