[MATRIX-SIG] Re: int. division

[Charles G. Waldman]

David J. C. Beach writes:
 > 
 > Allow me to reiterate Paul Dubois's argument.  Consider the code:
 > 
 >             x = i / j
 > 
 > Now, suppose i=2 and j=4.  Then x will be the integer, 2.  Everybody agrees
 > on this. 

Well, not everybody.  I would have 2/4 == 2.0 and 2//4 == 2
 
I think these are different mathematical operations; in one view,
division is an "inverse operation" to multiplication, just as
subtraction is the inverse operation to addition; just as

(-B) + A + B == A for all A and B  

I expect 

(1/B) * A*B == A for all nonzero B

[at least up to the limits of machine representation of real numbers]


In the other view,  division is the solution of the equation

xa + r = b, r<b

for an integer x, given integers a and b.

Both of these are useful notions and I'm not proposing we take any
feature out of the language, I would simply acknowledge that these two
are not the same operation and distinguish them with different
symbols.

 

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