From: Logan Capaldo <logancapaldo@...>
Date: 2006-02-17T08:20:11+09:00
Subject: Re: dot-product operators and strides for linear algebra

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On Feb 16, 2006, at 5:59 PM, <jam5238-001@yahoo.de> wrote:

> My assumption is  that is might be possible to extend ruby with  
> reasonable effort to add  the additional ".*" "./" and ".^2" binary  
> operators and the transpose /  conjugate transpose operators. For  
> the standard ruby this function  would just do the same as their  
> scalar conterparts, however, when  implementing a matrix class  
> these additional operators can become alive  and be used to  
> implement the elementwise dot operations.

That's an especially poor choice of operator name ;)

a * b == a.*(b)

You could add a method called .*, but you couldn't call it in the  
normal manner, you'd have to say:
a.send(".*", b)
which I don't think is what you were looking for. As for "strides",  
have you seen ranges?

0..9 # 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
1...10 # 1, 2, 3, 4, 5, 6, 7, 8, 9

As for having an alternative step, you can use #step,

1.step(10, 2) { |x| p x }
1
3
5
7
9

To turn a step into a range-like object (instead of a method) use an  
enumerator:

require 'enumerator'
zero_to_twentyfive_by_five = 0.to_enum(:step, 25, 5)

zero_to_twentyfive_by_five.each { |x| p x }
0
5
10
15
20
25

In 1.9 you don't even need to use the to_enum, ie you could simply write

zero_to_twentyfive_by_five = 0.step(25,5)






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