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Re: Semantics of vector operations

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Doug McNutt
January 23, 2004 16:21
Re: Semantics of vector operations
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I have been a lurker since early November. Dan S. suggested I get over here when I wrote a piece on the summary list describing my feelings about vector operations in perl 6. My information was based on the recent O'Reilly book and I had to confess that I have never in my life opened a CVS file. I did volunteer to help and I remain willing.

Luke Palmer also responded to my message and said I would be horrified to learn that  >>*<< was being called a "vector" operation rather than a "list" operation. I am horrified. Computer scientists have already usurped the terms "real", "kilo", and others and given them non-standard meanings. Please don't do the same with "vector" and "matrix". And forget I ever mentioned quaternion, tensor, and rotor.

I am a physicist and mathematician who uses perl5 extensively for the likes of preparing CAD data for printed circuit board fabrication and creating AutoDesk files in DXF format from mathematical calculations. I even plot data on my web site using perl to create .SVG files. I learned to code when FORTRAN didn't have any version number and I still think I might be happy with pure assembly in parrot but when I want to do vectors or complex numbers I end up in Waterloo Maple for the solutions and M$ Excel for the arithmetic. Perl 6 would sure be nice for once-in-a-while vector operations that are not worth the programming time for an array of 1024 Mac G5's.

This whole thread worrying about semantics of obscure operators for things that are not even going to be real vector or matrix operations worries me. Just who do you think is going to use them? Multiplying elements of an array by each other to get another array is not a vector product and it is not an inner product. It is useless to me regardless of the operator syntax you choose. Ditto for multiplication of lists of lists, also called matrices, where all you do is provide piece by piece multiplication of elements.

In FORTRAN I learned that names that begin with IJKLMN were integers and further that if only a single letter is used it will be assigned to a hardware register. Those letters are what you now call a sigl and I'll bet I spelled it wrong.

Why can't you assign a sigl to things that are to be vectors or matrices and let that determine what the standard operators do? Context could distinguish the inner product from the vector product.  typedef? Those of us who actually use vector arithmetic wouldn't mind a special identifier that's not an $, @, or %. Other users need not know about it until they find it useful. If absolutely necessary to comply with modern terminology you could call vectors and matrices members of a class and overload the operators but my experience is that such things just cloud the underlying arithmetic process that needs to be foremost while solving a problem.

The KISS principle is important. Please reconsider your "vector" operations before you go off the deep end with syntax that won't ever be used. And yes, I have some time and would like to help. But it will take hours to learn about the C++ stuff in CVS files. I have Linux and Mac OS neXt available.

Douglas P. McNutt	 PhD
The MacNauchtan Laboratory
7255 Suntide Place
Colorado Springs	 CO 80919-1060
voice 719 593 8192

-->  There are 10 kinds of people:  those who understand binary, and those who don't <--

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