'aspect 1' plot ((,-)2j1) ,: _1^(%~i:)60 NB. This makes the frame of the 
plot square, but it has different units on the two axes, so the circle is 
deformed. How do I make the circle circular?
   plot ((,-)2j1),:_1^(%~i:)60 NB. This is different, but not correct either.


>________________________________
> Fra: Linda Alvord <[email protected]>
>Til: [email protected] 
>Sendt: 3:39 lørdag den 21. september 2013
>Emne: Re: [Jprogramming] Plotting complex lists
> 
>
>Square isn't so square either.  Linda  (Yet again, life is a series of
>approximations.)
>
>-----Original Message-----
>From: [email protected]
>[mailto:[email protected]] On Behalf Of Bo Jacoby
>Sent: Wednesday, September 18, 2013 9:52 PM
>To: [email protected]
>Subject: Re: [Jprogramming] Plotting complex lists
>
>Thanks Linda! The 'aspect 1' makes the plot square. Do you know how to make
>circles circular?
>
>
>>________________________________
>> Fra: Linda Alvord <[email protected]>
>>Til: [email protected]
>>Sendt: 2:48 torsdag den 19. september 2013
>>Emne: Re: [Jprogramming] Plotting complex lists
>> 
>>
>>Try replacing the last line with:
>>
>>'aspect 1' plot circle,ellipse,:hyperbola
>>
>>Linda
>>
>>-----Original Message-----
>>From: [email protected]
>>[mailto:[email protected]] On Behalf Of Bo 
>>Jacoby
>>Sent: Tuesday, September 17, 2013 12:00 PM
>>To: [email protected]
>>Subject: Re: [Jprogramming] Plotting complex lists
>>
>>One benefit of using complex numbers is that you may forget about 
>>trigonometry.
>>
>>   load'plot'
>>   circle=._1^n=.(%~i:)60
>>   ellipse=.(circle*-.a)+(+circle)*a=.0.8
>>   hyperbola=.-:((+%)j.(-%))^n
>>   plot circle,ellipse,:hyperbola
>>   
>>
>>
>>
>>
>>
>>>________________________________
>>> Fra: km <[email protected]>
>>>Til: "[email protected]" <[email protected]>
>>>Sendt: 0:40 tirsdag den 17. september 2013
>>>Emne: Re: [Jprogramming] Plotting complex lists
>>> 
>>>
>>>Summary of results.  The strategy of hyperbola below (plotting a 
>>>complex
>>table) is not well known.  Henry Rich found it and reported it.
>>>
>>>Bo Jacoby gave the best way to change the sign of the real part of a
>>complex number.
>>>Simply do [: + -   .
>>>
>>>
>>>
>>>NB. Complex Analytic Geometry
>>>
>>>
>>>NB. How to calculate complex number lists and tables for NB. plotting 
>>>lines, circles, ellipses, and hyperbolas.  How to NB. modify these 
>>>tables to achieve translations, rotations, NB. and reflections.  Begin 
>>>with preliminaries:
>>>
>>>
>>>steps =: {.@] + -~/@] * [ %~ [: i. >:@[
>>>
>>>NB.  n steps a,b produces n+1 equally spaced values from a to b
>>>
>>>to =: 512 steps ,  NB. Usage a to b for 512 steps from a to b
>>>
>>>sin =: 1&o.
>>>
>>>cos =: 2&o.
>>>
>>>sinh =: 5&o.
>>>
>>>cosh =: 6&o.
>>>
>>>arcsinh =: _5&o.
>>>
>>>
>>>NB. Now, results
>>>
>>>
>>>line =: 2 : 'm + (n-m)*]'
>>>
>>>NB. A line B [ t is point "t of the way from A to B".  Command NB.
>>>NB.    plot 0 line 1j1 [ _1 to 2
>>>NB.
>>>NB. shows the line segment from _1j_1 to 2j2
>>>
>>>NB. You are plotting a list of 513 complex numbers.
>>>
>>>
>>>parabola =: 1 : '] j. (1 % 4 * m) * *:'
>>>
>>>NB. p parabola x produces point x j. y on parabola NB. (*: x) = 4*p*y 
>>>. Command NB.
>>>NB.    plot 1r4 parabola _2 to 2
>>>NB.
>>>NB. plots parabola y = *: x for x from _2 to 2
>>>
>>>NB. You are plotting a list of 513 complex numbers.
>>>
>>>
>>>ellipse =: 2 : '((m * cos) j. n * sin) 0 to 2p1'
>>>
>>>NB. Suggested by Henry Rich
>>>
>>>NB. Command
>>>NB.
>>>NB.    plot a ellipse b
>>>NB.
>>>NB. plots the ellipse 1 = (*: x % a) + *: y % b .
>>>
>>>NB. If a = b you get the circle (*: x) + (*: y) = *: a
>>>
>>>
>>>hyperbola =: 2 : '[: (,: +) (n * sinh) j. m * cosh'
>>>
>>>NB. Suggested by Henry Rich
>>>
>>>toh =: [: to/ [: arcsinh %~
>>>
>>>NB. b toh c,d is (arcsinh c%b) to (arcsinh d%b)
>>>
>>>NB. Command
>>>NB.
>>>NB.    plot a hyperbola b [ b toh c,d
>>>NB.
>>>NB. plots  y^2/a^2 - x^2/b^2 = 1  for x from c to d.
>>>
>>>NB. Remember the pattern b [ b toh c,d
>>>
>>>NB. You are plotting rows of a 2 by 513 table to get the two NB. 
>>>branches of the hyperbola.
>>>
>>>
>>>NB. Rotations, translations, and reflections
>>>
>>>NB. Multiply a complex number list or table by (^&j. theta) NB. to 
>>>rotate all of its points by theta radians.  The center NB. of rotation 
>>>is the origin 0 = 0j0 .
>>>
>>>NB. Add 5j3 to a complex list or table to move all of its points NB. 
>>>the distance and direction of 5j3 from 0j0.
>>>
>>>NB. Use (+ list) or (+ table) (monadic + is conjugate) to NB. reflect 
>>>all the points of the list or table across the NB. line through 0j0 
>>>and
>>>1j0 -- the x-axis.  Afterwards NB. multiply by (^&j. theta) to achieve 
>>>a reflection across NB. the line through 0j0 and (^&j. theta).
>>>
>>>NB. Multiply a positive number p times a list or table to NB. achieve 
>>>an expansion from 0 or compression toward 0 NB. according as  p > 1  
>>>or p < 1  .
>>>
>>>NB. If you want to combine several operations do the NB. reflection 
>>>first and the translation last.
>>>
>>>NB. Example
>>>NB.
>>>NB.    plot (^&j. theta) * p parabola _2 to 3 NB.
>>>NB. plots a parabola rotated by theta radians, with 0j0 NB. the center 
>>>of rotation.  If theta is _1r2p1 (that is NB. - pi%2 radians) you have 
>>>converted a  (*: x) = 4 * p * y NB. parabola into a  (*: y) = 4 * p * 
>>>x parabola.
>>>
>>>
>>>--Kip Murray
>>>
>>>Sent from my iPad
>>>
>>>----------------------------------------------------------------------
>>>For information about J forums see http://www.jsoftware.com/forums.htm
>>>
>>>
>>>
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>>
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>>
>>
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