-:<:sqrt 5
0.618034
,.(-:<:sqrt 5)^i.30
1
0.618034
0.381966
0.236068
0.145898
0.0901699
0.0557281
0.0344419
0.0212862
0.0131556
0.00813062
0.005025
0.00310562
0.00191938
0.00118624
0.000733137
0.000453104
0.000280034
0.00017307
0.000106963
6.6107e_5
4.08563e_5
2.52506e_5
1.56057e_5
9.64488e_6
5.96086e_6
3.68401e_6
2.27685e_6
1.40717e_6
8.69678e_7
+/(-:<:sqrt 5)^i.30
2.61803
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Linda Alvord
Sent: Friday, December 13, 2013 4:41 AM
To: [email protected]
Subject: Re: [Jprogramming] Under for fun & profit
-:<:sqrt 5
0.618034
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Roger Hui
Sent: Thursday, December 12, 2013 5:40 PM
To: Programming forum
Subject: Re: [Jprogramming] Under for fun & profit
sqrt1=: (] -:@+ %)^:_~
x -: *: sqrt1 x=: 100 ?@$ 1000
1
x -: *: sqrt1 x=: 100 ?@$ 0
1
On Thu, Dec 12, 2013 at 1:31 PM, Roger Hui <[email protected]>wrote:
> Ooops. A longer but correct solution. Can probably be shortened.
>
> sqrt=: (0.5 * ] + %)^:_ ~
> sqrt 3
> 1.73205
> sqrt 17
> 4.12311
>
>
>
>
> On Thu, Dec 12, 2013 at 1:29 PM, Roger Hui
<[email protected]>wrote:
>
>> sqrt=: -:@(+%)^:_~
>> sqrt 3
>> 1.78078
>> sqrt 17
>> 8.55842
>>
>>
>>
>> On Thu, Dec 12, 2013 at 1:22 PM, William Tanksley, Jr <
>> [email protected]> wrote:
>>
>>> I'm clueless -- how would you implement one of the more formally
>>> correct solutions (Newton's, Babylonian, exhaustive search, or
>>> random probing)? K did pretty well.
>>>
>>> -Wm
>>>
>>>
>>> On Thu, Dec 12, 2013 at 11:09 AM, Dan Bron <[email protected]> wrote:
>>> > There is a stack exchange dedicated to code golfing,
>>> > http://codegolf.stackexchange.com/ . During free moments at work,
>>> > I
>>> find
>>> > posting J solutions is a good way to relieve stress.
>>> >
>>> > Today I came across a competition to reimplement square root in as
>>> > few characters as possible [1]. Most languages copped out and
>>> > simply
>>> restated
>>> > sqrt as ^&0.5 to minimize their golf score. (I did this too, to
>>> > allow apples-to-apples comparisons).
>>> >
>>> > But the C++ entry caught my eye: exp(log(x)/2)) . This is an
>>> interesting
>>> > approach, and gives us an opportunity to highlight some of the
>>> advantages
>>> > of J's notaton. Leaving aside the question of syntax, even
>>> > expressing
>>> the
>>> > 4 primitives in that expression (exp, log, x, 2) would cost most
>>> languages
>>> > 8 characters. But not in J. In J, we do NOT need:
>>> >
>>> > - To name variables (so no "x")
>>> > - To name the constant 2 (in this particular case)
>>> > - To delimit functions from arguments using parentheses
>>> > - To explicitly instruct the intreprter to undo the log by
>>> > typing
>>> "exp".
>>> >
>>> > This last freebie is perhaps the most satisfying. We just tell
>>> > the interpreter that we want to operate "log space", and let J
>>> > figure out
>>> the
>>> > exp for itself.
>>> >
>>> > -:&.^.
>>> >
>>> > Six characters. Less than it takes to write "log" and "exp"
>>> > separated
>>> by a
>>> > single space!
>>> >
>>> > -Dan
>>> >
>>> > [1]
>>> >
>>> http://codegolf.stackexchange.com/questions/73/reimplementing-square
>>> -root/15856
>>> >
>>> > ------------------------------------------------------------------
>>> > ---- For information about J forums see
>>> > http://www.jsoftware.com/forums.htm
>>> --------------------------------------------------------------------
>>> -- For information about J forums see
>>> http://www.jsoftware.com/forums.htm
>>>
>>
>>
>
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