[Edu-sig] Textbooks

[Daniel Ajoy]

On 26 Feb 2006 at 8:55, kirby urner wrote:

> >
> > I just wanted to verify the claim that some Python modules
> > really incorporate J semantics.
> 
> 
> numpy incorporates the idea of 'rank' and 'axes' much the way J or other
> array based languages do i.e. you can shape numbers to have however many
> axes in some multidimensional box.  Then you can do operations on entire
> boxes, including in ways which combine them with each other.

I got this from a J document:

http://jsoftware.com/books/help/learning/07.htm

> In J, every verb has what might be called a natural, or 
> intrinsic, rank for its argument(s). Here are some examples 
> to illustrate. For the first example, consider:

*: 2 	
4

*: 2 3 4
4 9 16

> Here, the arithmetic function "square" naturally applies to 
> a single number(a 0-cell). When a rank-1 array (a list) is 
> supplied as argument, the function is applied separately to 
> each 0-cell of the argument. In other words, the natural 
> rank of (monadic) *: is 0. 

are you saying that functions in numpy also have intrinsic rank for
its arguments. Do some numpy functions have 0 rank regardless
of the rank of their arguments? 


> To be array based, and to use a semantics of tacit programming, appear to me
> as separable capabilities.  Numpy doesn't try to be like J in this latter
> sense.  APL isn't quite like J in this sense either, yet is array-based as
> well.
> 
> Kirby
> 

I agree, but Paul talked about J "semantics and behaviour". J has tacit
semantics so I was wondering if numpy also has this feature. You are saying
that numpy doesn't use tacit programming semantics.


Here is something I got from:

http://www.unb.ca/web/transpo/mynet/Iverson_APL.htm

> Tacit programming offers several advantages, including the following:
> 
> 1. It is concise.
> 2. It allows significant formal manipulation of definitions.
> 3. It greatly simplifies the introduction of programming into any topic.



Daniel




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