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Topic: Mathematica and Lisp
Replies: 16   Last Post: Mar 7, 2013 3:58 AM

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Christoph Lhotka

Posts: 41
Registered: 3/2/10
Re: Mathematica and Lisp
Posted: Mar 7, 2013 3:57 AM
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Dear group members,

At the beginning I did not want to enter this discussion at all, and
still I think it is not worthwhile doing so now.

I would just kindly like to ask you to give the right names for various
subject titles, and not to continue this thread under the one called "Mathematica and Lisp", since the content of your posts has nothing to do with this subject.

It is difficult enough to find the right information in the internet, one may be looking for, nowadays. If one tries to look up posts in this forum matching Lisp one is spammed by posts that have nothing to do with it.

This is annoying since Lisp and Mathematica are interesting subjects by themselves, and I would like to learn more about both of them.

I apologize that I have been entering your dispute about various things, and I hope you will find a common language soon.

Sincerely,

Christoph



On 03/06/2013 11:55 AM, Richard Fateman wrote:
> On 3/5/2013 7:54 PM, djmpark wrote:
>> Reverse the order of what? ArcTan of one argument has only one argument and
>> how can that be reversed? What has two arguments is the coordinate
>> specification {x, y} and they are not reversed in ArcTan[x, y].
>>
>> It is the one argument form ArcTan[y/x] that seems poorly designed and would
>> probably only be used when one knows the quotient and not x and y - so there
>> wouldn't be anything to reverse.
>>
>>
>> David Park
>> djmpark@comcast.net
>> http://home.comcast.net/~djmpark/index.html
>>
>>
>>
>>
>> From: Richard Fateman [mailto:fateman@cs.berkeley.edu]
>>
>> (simple example: why does Mathematica reverse the order of arguments to
>> arctan of 2 args?)
>>
>> RJf
>>
>>

> ArcTan[x,y] in Mathematica gives the ArcTan[y/x] but in the correct
> quadrant.
> atan2 (y,x) in FORTRAN gives the arctangent of y/x). Note the order of
> arguments.
> in C++
> in Pascal
> in Java
> in Lisp (atan y x)
> in PHP
> in Python v 3.3.0
> in Ruby
>
>
>
> I was able to find just one programming language that agrees with the
> order in Mathematica.
> That is Microsoft's Excel. Now it could be that compatibility with Excel is
> more important than compatibility with those other languages. Google
> docs has to
> use the same order as Excel, but I think it is generally recognized as being
> compatible with an error.
> Just sayin'.
> RJF
>
>
>
>
>
>
>
>
>






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