On Mon, Dec 10, 2012 at 5:33 AM, Doug McIlroy <d...@cs.dartmouth.edu> wrote:
> > > Matlab exploits them heavily (though represented as doubles). > > > Not sure what you are referring to > > I had in mind Matlab's frequent use of a Boolean array as > a characteristic function describing some property of the > elements of another array. Such arrays are used to control > other array operations. In this usage, the characteristic > array may be optimized out of existense, but it fosters > higher-level thinking and concise code. > In which case it goes back to APL's compress operator ie 1960. http://www.aplusdev.org/APlusRefV2_8.html#HEADING179 Heres a session that demonstrates A+ Copyright (c) 1990-2008 Morgan Stanley. All rights reserved. This version is Release 4.22 a ← 1 2 3 4 5 b ← 1 0 1 1 0 b/a 1 3 4 b ← 1 0 2 1 0 b/a 1 3 3 4 -- http://www.the-magus.in http://blog.languager.org
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