Just to stir the pot, here is a definition from script
~system/main/validate.ijs which I found in J602:
iscomplex=: -. @ (-: +) :: 0:
iscomplex 1
0
iscomplex 1j0
0
iscomplex 1j2
1
iscomplex 1j0 2j0
0
iscomplex 1j0 2j3
1
iscomplex 1.2 1j2
1
iscomplex 'a'
0
Kip
On 1/22/2012 2:14 PM, Linda Alvord wrote:
> How can you create a number in the complex plane that happens to lie on the
> real axis? How do you keep its complexness?
>
> a=:(i.6)j.0
> a
> 0 1 2 3 4 5
>
> Even when you use j. the numbers have moved into the set of real numbers.
>
> Linda.
>
> -----Original Message-----
> From: programming-boun...@jsoftware.com
> [mailto:programming-boun...@jsoftware.com] On Behalf Of Henry Rich
> Sent: Sunday, January 22, 2012 12:09 PM
> To: Programming forum
> Subject: Re: [Jprogramming] 5|0 1 2 3 4 is not equal to 5|0 1 2 3 4 j.0
>
> As Don said, make sure you understand complex floor before you start coding.
>
> Henry Rich
>
> On 1/22/2012 11:38 AM, Marshall Lochbaum wrote:
>> The theory of moduli is based on the quotient group of the integers by a
>> subgroup. For instance, the integers (mod 2) are produced by taking all
> the
>> integers and identifying all the ones that are even, as well as all the
>> ones that are odd. Then we get a two-element group which we can preform
>> addition on: even+even=even, even+odd=odd, etc.
>>
>> To reduce a number in a particular modulus, we need to find a canonical
>> representation for that number. For positive numbers n the choice is
> fairly
>> simple: n|l gives the l' such that 0<=l'<n. In the complex plane, a number
>> generates a grid by taking its product with the Gaussian integers; try
>> 'dot; pensize 2' plot , 1j2 * j./~i:10
>> to see what I mean. Then what we want is a canonical form for what happens
>> when we identify all those points together. We're allowed to "shift" by
> any
>> Gaussian integer times the modulus.
>>
>> Based on this, I think a good way to calculate the modulus is to get the
>> number into the square that lies counterclockwise of the modulus number.
>> Practically, this means we decompose a complex number y into (a j.b)*x,
> and
>> then return (1|a)j.(1|b) .
>>
>> I'll see if I can get around to editing this. I have a working copy of the
>> source, but I haven't made sense of it entirely.
>>
>> Marshall
>>
>> On Sun, Jan 22, 2012 at 10:45 AM, Raul Miller<rauldmil...@gmail.com>
> wrote:
>>
>>> Yes, this is a bug.
>>>
>>> Someone should fix it.
>>>
>>> J is open source. (Though distributed sources do not compile for me,
>>> and I keep getting sidetracked when I investigate forks that might
>>> compile.)
>>>
>>> --
>>> Raul
>>> ----------------------------------------------------------------------
>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>
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>>
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