We can do an angelic solution using "larger absolute value" in place of bitwise 
OR.

    lav =: [`]@.(|@[ < |@])"0  NB. larger absolute value
    A
 1 2j3
 0   4
    (lav +@|:) A
    1 2j3
 2j_3   4
    
Kip Murray

Sent from my iPad


On Jan 15, 2013, at 5:20 PM, Henry Rich <[email protected]> wrote:

> Nah, that's not beyond impish.  The devilish solution is to take the bitwise 
> OR of the matrix with its conjugate transpose (but that's easier in assembler 
> language than in J:
> (23 b.&.(a.&i.)&.(2&(3!:5))&.+. +@|:))
> ).  And you need to be sure that the zeros on the lower diagonal and below 
> are true zeros!
> 
> Henry Rich
> 
> On 1/15/2013 6:03 PM, km wrote:
>> Oh, boy!  (v1`v2) } y <--> (v1 y) } (v2 y)
>> 
>> Brief and devilish, take care for your soul, Henry!
>> 
>> --Kip
>> 
>> Sent from my iPad
>> 
>> 
>> On Jan 15, 2013, at 3:39 PM, Henry Rich <[email protected]> wrote:
>> 
>>>   hft =: 0&=`(,: +@|:)}
>>> 
>>> Henry Rich
>>> 
>>> On 1/15/2013 5:25 AM, km wrote:
>>>> This is an easy one.  A Hermitian matrix matches its conjugate transpose.  
>>>> Write a verb hft that creates a Hermitian matrix from a triangular one 
>>>> that has a real diagonal.
>>>> 
>>>>     ishermitian =: -: +@|:
>>>>     ]A =: 2 2 $ 1 2j3 0 4
>>>>  1 2j3
>>>>  0   4
>>>>     ]B =: hft A
>>>>     1 2j3
>>>>  2j_3   4
>>>>     ishermitian A
>>>>  0
>>>>     ishermitian B
>>>>  1
>>>> 
>>>> Kip Murray
>>>> 
>>>> Sent from my iPad
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