[Jprogramming] Clean

[Cliff Reiter]

Is there a reason to prefer (*|@*) over (**|)?

    ts=:6!:2 , 7!:2@]
    1000 ts'(* |@*)&.+. ^ 0j1 * 1r2p1 * i. 500'
0.00106239 43200
    1000 ts'(**|)&.+. ^ 0j1 * 1r2p1 * i. 500'
0.000791911 43072

Best, Cliff

On 5/27/2013 1:34 AM, km wrote:
> I didn't think of Signum!  Thanks, Roger.
>
> Sent from my iPad
>
>
> On May 26, 2013, at 11:56 PM, Roger Hui <rogerhui.canada at gmail.com> wrote:
>
>> clean=: (* |@*)&.+.
>>
>> Eugene McDonnell objected when we made *x to be 0 for x near 0, saying that
>> *x should be 0 only if x is 0.
>>
>>
>> On Sun, May 26, 2013 at 9:32 PM, km <km at math.uh.edu> wrote:
>>
>>> Let's say a real number "ought to be zero" if its absolute value is <: the
>>> comparison tolerance 2^_44 .  Write a verb "clean" that replaces real
>>> numbers that ought to be zero with zero.  How would you clean a complex
>>> number?
>>>
>>>     1 o. 1r2p1 * i. 5
>>> 0 1 1.22465e_16 _1 _2.44929e_16
>>>     clean 1 o. 1r2p1 * i. 5
>>> 0 1 0 _1 0
>>>
>>>     ^ 0j1 * 1r2p1 * i. 5
>>> 1 6.12323e_17j1 _1j1.22465e_16 _1.83697e_16j_1 1j_2.44929e_16
>>>     clean ^ 0j1 * 1r2p1 * i. 5
>>> 1 0j1 _1 0j_1 1
>>>
>>> --Kip Murray
>>>
>>> Sent from my iPad
>>>
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-- 
Clifford A. Reiter
Lafayette College, Easton, PA 18042
http://webbox.lafayette.edu/~reiterc/