[Numpy-discussion] Complex arange

Robert Kern robert.kern@gmail....
Thu Feb 1 19:47:33 CST 2007


Russel Howe wrote:
>> arange(1j, 5j, 1) do? Numeric raises an exception here, and I thing  
>> numpy
>> should, too.
> 
> The same as arange(1, 5, 1j) - an empty array since it takes 0 of the  
> step to cross the distance. 

I'm not sure that's really the answer. I think it's simply not defined. No
number of steps (which is different than 0 steps) along the imaginary axis will
take 1+0j to 5+0j.

> But something like
> arange(1j, 5j, 1j) seems fine.  As does arange(1j, 3+5j, 2+1j) which  
> should give [ 1j, 2+2j ].  The idea is to walk by step up to the edge  
> of the box.  I seem to recall a discussion of why this was a bad idea  
> a while ago on this list, but I can't find it...

Box? *Aaah*! You're looking at z1 placing distinct upper(lower) bounds on the
real and imaginary parts rather than specifying a point target. That's
a...unique perspective.  ;-)

But then, I'm of the opinion that arange() should be reserved for integers, and
the other use cases are better served by linspace() instead.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco


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