DoubleArray.st
author Claus Gittinger <cg@exept.de>
Tue, 14 Nov 1995 20:02:34 +0100
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 COPYRIGHT (c) 1993 by Claus Gittinger
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	      All Rights Reserved
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 This software is furnished under a license and may be used
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 only in accordance with the terms of that license and with the
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 inclusion of the above copyright notice.   This software may not
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 be provided or otherwise made available to, or used by, any
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 other person.  No title to or ownership of the software is
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 hereby transferred.
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ArrayedCollection variableDoubleSubclass:#DoubleArray
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       instanceVariableNames:''
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       classVariableNames:''
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       poolDictionaries:''
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       category:'Collections-Arrayed'
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!
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!DoubleArray class methodsFor:'documentation'!
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copyright
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 COPYRIGHT (c) 1993 by Claus Gittinger
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	      All Rights Reserved
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 This software is furnished under a license and may be used
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 only in accordance with the terms of that license and with the
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 inclusion of the above copyright notice.   This software may not
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 be provided or otherwise made available to, or used by, any
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 other person.  No title to or ownership of the software is
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 hereby transferred.
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!
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version
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    ^ '$Header: /cvs/stx/stx/libbasic/DoubleArray.st,v 1.11 1995-11-11 14:31:28 cg Exp $'
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!
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documentation
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    DoubleArrays store doubleFloats values (and nothing else).
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    They have been added to support heavy duty number crunching somewhat
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    better than other smalltalks do. 
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    Storing Floats & Doubles in these objects (instead of Arrays)
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    has some benefits:
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    1) since the values are stored directly (instead of pointers to them)
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       both access overhead and garbage collect overhead is minimized.
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    2) they can be much faster passed to c functions (such as graphics 
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       libraries or heavy duty math packages), since the double values
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       come packed and can be used in C by using a (double *) or double[].
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       There is no need to loop over the array extracting doubles.      
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    3) they could (in theory) be much more easily be processed by things like
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       vector and array processors
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    Be aware however, that Float- and DoubleArrays are not supported in other
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    smalltalks - your program will thus become somewhat less portable.
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    (since their protocol is the same as normal arrays filled with floats,
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     they can of course be easily simulated - a bit slower though)
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    Also, they could be simulated by a ByteArray, using doubleAt: and 
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    doubleAtPut: messages to access the elements, but that seems a bit
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    clumsy and unelegant. Also, the stc-compiler may learn how to deal
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    with Float- and DoubleArrays, making accesses very fast in the future.
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    Of course, DoubleArray can be subclasses and named instance variables
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    be added.
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    See example uses in the GLX interface and GLDemos.
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! !